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WO2014014114A1 - Composition de formation de couche de passivation, substrat semi-conducteur à couche de passivation, procédé de fabrication de substrat semi-conducteur à couche de passivation, élément de cellule solaire, procédé de fabrication d'élément de cellule solaire, et cellule solaire - Google Patents

Composition de formation de couche de passivation, substrat semi-conducteur à couche de passivation, procédé de fabrication de substrat semi-conducteur à couche de passivation, élément de cellule solaire, procédé de fabrication d'élément de cellule solaire, et cellule solaire Download PDF

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Publication number
WO2014014114A1
WO2014014114A1 PCT/JP2013/069704 JP2013069704W WO2014014114A1 WO 2014014114 A1 WO2014014114 A1 WO 2014014114A1 JP 2013069704 W JP2013069704 W JP 2013069704W WO 2014014114 A1 WO2014014114 A1 WO 2014014114A1
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Prior art keywords
passivation
passivation layer
composition
layer
group
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PCT/JP2013/069704
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English (en)
Japanese (ja)
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WO2014014114A9 (fr
Inventor
剛 早坂
吉田　誠人
野尻　剛
倉田　靖
田中　徹
明博 織田
修一郎 足立
服部　孝司
三江子 松村
敬司 渡邉
真年 森下
浩孝 濱村
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Resonac Corp
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Hitachi Chemical Co Ltd
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Priority to JP2014525898A priority Critical patent/JP6269484B2/ja
Priority to CN201380038106.4A priority patent/CN104508830A/zh
Publication of WO2014014114A1 publication Critical patent/WO2014014114A1/fr
Publication of WO2014014114A9 publication Critical patent/WO2014014114A9/fr
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/30—Coatings
    • H10F77/306—Coatings for devices having potential barriers
    • H10F77/311—Coatings for devices having potential barriers for photovoltaic cells
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F10/00—Individual photovoltaic cells, e.g. solar cells
    • H10F10/10—Individual photovoltaic cells, e.g. solar cells having potential barriers
    • H10F10/14—Photovoltaic cells having only PN homojunction potential barriers
    • H10F10/146—Back-junction photovoltaic cells, e.g. having interdigitated base-emitter regions on the back side
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F71/00—Manufacture or treatment of devices covered by this subclass
    • H10F71/121—The active layers comprising only Group IV materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/547—Monocrystalline silicon PV cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a composition for forming a passivation layer, a semiconductor substrate with a passivation layer, a method for manufacturing a semiconductor substrate with a passivation layer, a solar cell element, a method for manufacturing a solar cell element, and a solar cell.
  • n-type diffusion layer is uniformly formed by performing several tens of minutes at 800 ° C. to 900 ° C.
  • n-type diffusion layers are formed not only on the front surface, which is the light receiving surface, but also on the side surface and the back surface. Therefore, side etching is performed to remove the n-type diffusion layer formed on the side surface.
  • the n-type diffusion layer formed on the back surface needs to be converted into a p + -type diffusion layer.
  • an aluminum paste is applied to the entire back surface, and this is heat-treated (fired), thereby forming an aluminum electrode together with the ohmic contact by converting the n-type diffusion layer into the p + -type diffusion layer. It has gained.
  • the aluminum electrode formed from the aluminum paste has low conductivity. Therefore, in order to reduce the sheet resistance, the aluminum electrode formed on the entire back surface usually must have a thickness of about 10 ⁇ m to 20 ⁇ m after heat treatment (firing). Furthermore, since the coefficient of thermal expansion differs greatly between silicon and aluminum, a large internal stress is generated in the silicon substrate during the heat treatment (firing) and cooling in the silicon substrate on which the aluminum electrode is formed, and the grain boundary Cause damage, crystal defect growth and warpage.
  • a point contact method has been proposed in which an aluminum paste is applied to a part of the surface of a silicon substrate to partially form a p + -type diffusion layer and an aluminum electrode (for example, Japanese Patent No. 3107287). (See the publication).
  • an aluminum paste is applied to a part of the surface of a silicon substrate to partially form a p + -type diffusion layer and an aluminum electrode.
  • back surface In the case of a solar cell having a point contact structure on the surface opposite to the light receiving surface (hereinafter also referred to as “back surface”), it is necessary to suppress the recombination rate of minority carriers on the surface of the portion other than the aluminum electrode. is there.
  • an SiO 2 film or the like has been proposed as a passivation layer for the back surface (see, for example, JP-A-2004-6565).
  • Such a passivation effect is generally called a field effect, and an aluminum oxide (Al 2 O 3 ) film or the like has been proposed as a material having a negative fixed charge (see, for example, Japanese Patent No. 4767110).
  • Such a passivation layer is generally formed by a method such as an ALD (Atomic Layer Deposition) method or a CVD (Chemical Vapor Deposition) method (for example, Journal of Applied Physics, 104 (2008), 113703-1). 113703-7).
  • the methods described in Journal of Applied Physics, 104 (2008), 113703-1 to 113703-7 involve complicated manufacturing processes such as vapor deposition, and it may be difficult to improve productivity.
  • the composition for forming a passivation layer used in the methods described in Thin Solid Films, 517 (2009), 6327-6330 and Chinese Physics Letters, 26 (2009), 088102-1-088102-4 is a gel over time. It is difficult to say that the storage stability is sufficient because of problems such as crystallization.
  • a passivation layer having an excellent passivation effect using an oxide containing a metal element other than aluminum has not been sufficiently studied so far.
  • the present invention has been made in view of the above-described conventional problems, and can form a passivation layer having a desired shape by a simple method, and has excellent storage stability and coating film uniformity. It is an object to provide a forming composition. Another object of the present invention is to provide a semiconductor substrate with a passivation layer, a solar cell element and a solar cell using the composition for forming a passivation layer. Furthermore, this invention makes it a subject to provide the manufacturing method of a semiconductor substrate with a passivation layer and a solar cell element using this composition for formation of a passivation layer.
  • a composition for forming a passivation layer comprising a compound represented by the following general formula (I) and at least one selected from the group consisting of a fatty acid amide, a polyalkylene glycol compound and an organic filler.
  • M includes at least one metal element selected from the group consisting of Nb, Ta, V, Y, and Hf.
  • R 1 independently represents an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 14 carbon atoms.
  • m represents an integer of 1 to 5.
  • composition for forming a passivation layer according to ⁇ 1> further comprising a compound represented by the following general formula (II).
  • each R 2 independently represents an alkyl group having 1 to 8 carbon atoms.
  • n represents an integer of 0 to 3.
  • X 2 and X 3 each independently represent an oxygen atom or a methylene group.
  • R 3 , R 4 and R 5 each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
  • ⁇ 3> The passivation according to ⁇ 1> or ⁇ 2>, including the polyalkylene glycol compound, wherein the polyalkylene glycol compound includes at least one selected from compounds represented by the following general formula (III): Layer forming composition.
  • R 6 and R 7 each independently represent a hydrogen atom or an alkyl group, and R 8 represents an alkylene group.
  • n is an integer of 3 or more.
  • a plurality of R 8 may be the same or different.
  • ⁇ 4> The fatty acid amide containing the fatty acid amide, the compound represented by the following general formula (1), the compound represented by (2), the compound represented by (3), and (4)
  • R 9 CONH 2 (1) R 9 CONH-R 10 -NHCOR 9 (2) R 9 NHCO—R 10 —CONHR 9 (3) R 9 CONH—R 10 —N (R 11 ) 2 ... (4)
  • R 9 and R 11 each independently represents an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms
  • 10 represents an alkylene group having 1 to 10 carbon atoms.
  • a plurality of R 11 may be the same or different.
  • ⁇ 6> a semiconductor substrate;
  • a passivation layer which is a heat treatment product of the composition for forming a passivation layer according to any one of ⁇ 1> to ⁇ 5>, provided on the entire surface or a part of the semiconductor substrate;
  • a semiconductor substrate with a passivation layer is a semiconductor substrate.
  • ⁇ 7> forming a composition layer by applying the passivation layer forming composition according to any one of ⁇ 1> to ⁇ 5> to the entire surface or a part of the semiconductor substrate; Heat-treating the composition layer to form a passivation layer; The manufacturing method of the semiconductor substrate with a passivation layer which has this.
  • ⁇ 8> a semiconductor substrate in which a p-type layer and an n-type layer are pn-junction;
  • a passivation layer which is a heat treatment product of the composition for forming a passivation layer according to any one of ⁇ 1> to ⁇ 5>, provided on the entire surface or a part of the semiconductor substrate;
  • An electrode disposed on one or more layers selected from the group consisting of the p-type layer and the n-type layer;
  • a solar cell element having
  • a passivation layer-forming composition that can form a passivation layer having a desired shape by a simple technique, is excellent in storage stability, and is excellent in coating film uniformity.
  • a semiconductor substrate with a passivation layer obtained using a composition for forming a passivation layer and having a passivation layer having an excellent passivation effect, a method for manufacturing a semiconductor substrate with a passivation layer, and excellent conversion efficiency are provided.
  • a solar cell element, a method for manufacturing a solar cell element, and a solar cell can be provided.
  • the term “process” is not only an independent process, but is included in this term if the purpose of the process is achieved even if it cannot be clearly distinguished from other processes.
  • a numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
  • the content of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. Means.
  • the term “layer” includes a configuration of a shape formed in part in addition to a configuration of a shape formed on the entire surface when observed as a plan view.
  • composition for forming a passivation layer of the present invention is a group consisting of a compound represented by the following general formula (I) (hereinafter also referred to as “compound of formula (I)”), a fatty acid amide, a polyalkylene glycol compound and an organic filler. And at least one selected from the following (hereinafter also referred to as “specific compound”).
  • the composition for forming a passivation layer may further contain other components as necessary.
  • M includes at least one metal element selected from the group consisting of Nb, Ta, V, Y, and Hf.
  • R 1 independently represents an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 14 carbon atoms.
  • m represents an integer of 1 to 5. When m is 2 or more, a plurality of groups represented by R 1 may be the same or different.
  • a passivation layer having an excellent passivation effect can be formed into a desired shape by applying a composition for forming a passivation layer containing the above components to a semiconductor substrate and heat-treating (baking) the composition.
  • the composition for forming a passivation layer contains the compound of formula (I), so that the occurrence of problems such as gelation is suppressed and the storage stability with time is excellent.
  • the composition for forming a passivation layer is excellent in coating film uniformity by including a specific compound.
  • the method using the composition for forming a passivation layer of the present invention is a simple and highly productive method that does not require a vapor deposition apparatus or the like. Further, the passivation layer can be formed in a desired shape without requiring a complicated process such as mask processing.
  • the passivation effect of a semiconductor substrate refers to the effective lifetime of minority carriers in a semiconductor substrate provided with a passivation layer by using a device such as Nippon Semilab Co., Ltd., WT-2000PVN, Sinton Instruments, WCT-120, etc. It can be evaluated by using the reflection microwave conductive attenuation method.
  • the effective lifetime ⁇ is expressed by the following equation (A) by the bulk lifetime ⁇ b inside the semiconductor substrate and the surface lifetime ⁇ s of the semiconductor substrate surface.
  • ⁇ s becomes long, resulting in a long effective lifetime ⁇ .
  • the bulk lifetime ⁇ b is increased and the effective lifetime ⁇ is increased. That is, by measuring the effective lifetime ⁇ , the interface characteristics between the passivation layer and the semiconductor substrate and the internal characteristics of the semiconductor substrate such as dangling bonds can be evaluated.
  • the storage stability of the composition for forming a passivation layer can be evaluated by a change in viscosity over time.
  • the composition for forming a passivation layer immediately after preparation has a shear viscosity ( ⁇ 0 ) at 25 ° C. and a shear rate of 1.0 s ⁇ 1 , and a passivation after storage at 25 ° C. for 30 days.
  • Evaluation can be made by comparing the shear viscosity ( ⁇ 30 ) at 25 ° C. and a shear rate of 1.0 s ⁇ 1 of the composition for layer formation, for example, by evaluating the rate of change in viscosity (%) over time. Can do.
  • the rate of change in viscosity (%) over time is obtained by dividing the absolute value of the difference in shear viscosity immediately after preparation and 30 days later by the shear viscosity immediately after preparation, and is specifically calculated by the following equation.
  • the viscosity change rate of the composition for forming a passivation layer is preferably 30% or less, more preferably 20% or less, and still more preferably 10% or less.
  • Viscosity change rate (%)
  • the coating film uniformity of the composition for forming a passivation layer is determined by whether or not the composition for forming a passivation layer is present in the entire application portion on the semiconductor substrate when the composition for forming a passivation layer is applied to the semiconductor substrate. It is evaluated by what.
  • the composition for forming a passivation layer contains at least one compound represented by the general formula (I).
  • the compound of formula (I) is a compound called a metal alkoxide.
  • the compound of formula (I) becomes a metal oxide of M in formula (I) by heat treatment (firing).
  • a passivation layer having an excellent passivation effect can be formed. The reason for this can be considered as follows.
  • the oxide formed by heat-treating (firing) the passivation layer-forming composition containing the compound of formula (I) is likely to be in an amorphous state, and defects such as metal atoms are generated and fixed near the interface with the semiconductor substrate. It is thought that it can have a charge. This negative fixed charge generates an electric field in the vicinity of the interface of the semiconductor substrate, so that the concentration of minority carriers can be reduced. As a result, the carrier recombination rate at the interface is suppressed, so that an excellent passivation effect is obtained. It is thought that it is played.
  • the fixed charge of the passivation layer can be evaluated by the CV method (Capacitance Voltage measurement).
  • the surface state density of the passivation layer formed from the composition for forming a passivation layer of the present invention may be larger than that of a metal oxide layer formed by an ALD method or a CVD method.
  • passivation layer forming a passivation layer formed from the composition of the present invention the concentration of electric field effect is increased minority carrier surface lifetime tau s becomes longer decreases. Therefore, the surface state density is not a relative problem.
  • M contains at least one metal element selected from the group consisting of Nb, Ta, V, Y, and Hf.
  • M preferably contains at least one metal element selected from the group consisting of Nb, Ta and Y, and more preferably contains Nb.
  • M preferably contains at least one metal element selected from the group consisting of Nb, Ta, V, and Hf, and Nb, Ta, VO And at least one selected from the group consisting of Hf.
  • R 1 each independently represents an alkyl group or an aryl group having 6 to 14 carbon atoms having 1 to 8 carbon atoms, if R 1 there are a plurality, R 1 is different from each other in the same May be.
  • R 1 is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms.
  • the alkyl group represented by R 1 may be linear or branched.
  • alkyl group represented by R 1 examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, hexyl, octyl, 2- An ethylhexyl group etc. can be mentioned.
  • Specific examples of the aryl group represented by R 1 include a phenyl group.
  • the alkyl group and aryl group represented by R 1 may have a substituent. Examples of the substituent for the alkyl group include a halogen atom, an amino group, a hydroxyl group, a carboxyl group, a sulfone group, and a nitro group.
  • R 1 is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, and more preferably an unsubstituted alkyl group having 1 to 4 carbon atoms, from the viewpoint of storage stability and a passivation effect.
  • m represents an integer of 1 to 5. From the viewpoint of storage stability, m is preferably 5 when M is Nb, m is preferably 5 when M is Ta, and M is VO. M is preferably 3, m is preferably 3 when M is Y, and m is preferably 4 when M is Hf.
  • the compound represented by the general formula (I) is composed of a compound in which m is 1 to 5 and R 1 is independently an alkyl group having 1 to 4 carbon atoms from the viewpoint of storage stability and a passivation effect. Preferably, it is at least one selected from the group, m is 1 to 5, and R 1 is at least one selected from the group consisting of compounds having an unsubstituted alkyl group having 1 to 4 carbon atoms. Is more preferable.
  • Compounds represented by the general formula (I) are niobium methoxide, niobium ethoxide, niobium isopropoxide, niobium n-propoxide, niobium n-butoxide, niobium t-butoxide, niobium isobutoxide, tantalum methoxide, tantalum.
  • tantalum isopropoxide, tantalum n-propoxide, tantalum n-butoxide, tantalum t-butoxide, tantalum isobutoxide, yttrium methoxide, yttrium ethoxide, yttrium isopropoxide, yttrium n-propoxide, yttrium n- Butoxide, yttrium t-butoxide, yttrium isobutoxide, vanadium methoxide oxide, vanadium ethoxide oxide, vanadium isopropoxide oxide, vanadium n-propoxide oxide Vanadium n-butoxide oxide, vanadium t-butoxide oxide, vanadium isobutoxide oxide, hafnium methoxide, hafnium ethoxide, hafnium isopropoxide, hafnium n-propoxide, hafnium n-butoxide, hafnium me
  • niobium ethoxide, niobium n-propoxide, niobium n-butoxide, tantalum ethoxide, tantalum n-propoxide, tantalum n-butoxide, vanadium ethoxide oxide, vanadium n-propoxy Preference is given to oxides, vanadium n-butoxide oxide, hafnium ethoxide, hafnium n-propoxide and hafnium n-butoxide.
  • the compound represented by the general formula (I) may be a prepared product or a commercially available product.
  • Commercially available products include, for example, pentamethoxyniobium, pentaethoxyniobium, penta-i-propoxyniobium, penta-n-propoxyniobium, penta-i-butoxyniobium, penta-n-butoxyniobium from High Purity Chemical Laboratory, Inc.
  • Penta-sec-butoxy niobium pentamethoxy tantalum, pentaethoxy tantalum, penta-i-propoxy tantalum, penta-n-propoxy tantalum, penta-i-butoxy tantalum, penta-n-butoxy tantalum, penta-sec-butoxy tantalum , Penta-t-butoxytantalum, vanadium (V) trimethoxide oxide, vanadium (V) triethoxy oxide, vanadium (V) tri-i-propoxide oxide, vanadium (V) tri-n-propoxide oxide, vanadium (V Tri-i-butoxide oxide, vanadium (V) tri-n-butoxide oxide, vanadium (V) tri-sec-butoxide oxide, vanadium (V) tri-t-butoxide oxide, tri-i-propoxy yttrium, tri-n -Butoxy yttrium, tetramethoxy
  • a halide of a specific metal (M) and an alcohol are reacted in the presence of an inert organic solvent, and ammonia or an amine compound is used to further extract the halogen.
  • Known methods such as a method of adding (Japanese Patent Laid-Open No. 63-227593 and Japanese Patent Laid-Open No. 3-291247) can be used.
  • the compound represented by the general formula (I) may be used as a compound in which a chelate structure is formed by mixing with a compound having a specific structure having two carbonyl groups.
  • a compound having a chelate structure at least a part of the alkoxide group of the compound of formula (I) is substituted with a compound having a specific structure to form a chelate structure.
  • a liquid medium may be present, or heat treatment, addition of a catalyst, and the like may be performed.
  • the stability of the compound of formula (I) to hydrolysis and polymerization reaction is improved, and the storage stability of the composition for forming a passivation layer containing the compound is further improved. To do.
  • the compound having a specific structure having two carbonyl groups is preferably at least one selected from the group consisting of ⁇ -diketone compounds, ⁇ -ketoester compounds and malonic acid diesters from the viewpoint of storage stability.
  • ⁇ -diketone compounds include acetylacetone, 3-methyl-2,4-pentanedione, 2,3-pentanedione, 3-ethyl-2,4-pentanedione, and 3-butyl-2,4-pentane.
  • Examples include dione, 2,2,6,6-tetramethyl-3,5-heptanedione, 2,6-dimethyl-3,5-heptanedione, 6-methyl-2,4-heptanedione, and the like.
  • ⁇ -ketoester compounds include methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, isopropyl acetoacetate, isobutyl acetoacetate, butyl acetoacetate, t-butyl acetoacetate, pentyl acetoacetate, isopentyl acetoacetate, acetoacetate Hexyl, n-octyl acetoacetate, heptyl acetoacetate, 3-pentyl acetoacetate, ethyl 2-acetylheptanoate, ethyl 2-methylacetoacetate, ethyl 2-butylacetoacetate, ethyl hexylacetoacetate, 4,4-dimethyl-3- Ethyl oxovalerate, ethyl 4-methyl-3-oxovalerate, ethyl 2-ethylacetoacetate, methyl
  • malonic acid diester examples include dimethyl malonate, diethyl malonate, dipropyl malonate, diisopropyl malonate, dibutyl malonate, di-t-butyl malonate, dihexyl malonate, t-butylethyl malonate, methyl malonate
  • examples include diethyl, diethyl ethylmalonate, diethyl isopropylmalonate, diethyl butylmalonate, diethyl sec-butylmalonate, diethyl isobutylmalonate, diethyl 1-methylbutylmalonate, and the like.
  • the number of chelate structures is not particularly limited as long as it is 1 to 5.
  • the number of carbonyl groups contributing to the chelate structure is not particularly limited, but when M is Nb, the number of carbonyl groups contributing to the chelate structure is preferably 1 to 5, and when M is Ta, the chelate structure It is preferable that the number of carbonyl groups contributing to 1 is 5 to 1.
  • M VO, it contributes to the chelate structure, but preferably 1 to 3, and when M is Y, it contributes to the chelate structure.
  • the number of carbonyl groups to be converted is preferably 1 to 3, and when M is Hf, the number of carbonyl groups contributing to the chelate structure is preferably 1 to 4.
  • the number of chelate structures can be controlled, for example, by appropriately adjusting the ratio of mixing the compound of formula (I) with a compound capable of forming a chelate with a metal element. Moreover, you may select suitably the compound which has a desired structure from a commercially available metal chelate compound.
  • a chelate structure in the compound of formula (I) can be confirmed by a commonly used analytical method. For example, it can be confirmed using an infrared spectrum, a nuclear magnetic resonance spectrum or a melting point.
  • the state of the compound of formula (I) may be liquid or solid.
  • the compound represented by the general formula (I) is a normal temperature (25 C.) and is preferably liquid.
  • the compound of formula (I) is a solid, it is a compound having good solubility or dispersibility in a solvent from the viewpoint of the passivation effect of the formed passivation layer, the storage stability of the composition for forming a passivation layer, and the like. It is preferable that it is a compound that is stable when it is used as a solution or dispersion.
  • the content of the compound of formula (I) contained in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the content of the compound of formula (I) can be 1% by mass to 80% by mass in the composition for forming a passivation layer from the viewpoint of storage stability and passivation effect, and is 3% by mass to 70% by mass. It is preferably 5% by mass to 60% by mass, more preferably 10% by mass to 50% by mass.
  • composition for forming a passivation layer of the present invention preferably further contains at least one compound represented by the following general formula (II) (hereinafter sometimes referred to as “specific organoaluminum compound”).
  • each R 2 independently represents an alkyl group having 1 to 8 carbon atoms.
  • n represents an integer of 0 to 3.
  • X 2 and X 3 each independently represent an oxygen atom or a methylene group.
  • R 3 , R 4 and R 5 each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
  • the specific organoaluminum compound includes compounds called aluminum alkoxide, aluminum chelate and the like, and preferably has an aluminum chelate structure in addition to the aluminum alkoxide structure. Further, as described in Nippon Seramikkusu Kyokai Gakujitsu Ronbunshi, vol. 97, pp369-399 (1989), the organoaluminum compound becomes aluminum oxide (Al 2 O 3 ) by heat treatment (firing). At this time, since the formed aluminum oxide tends to be in an amorphous state, a larger negative fixed charge can be obtained. As a result, it is considered that a passivation layer having an excellent passivation effect can be formed.
  • the passivation effect is further enhanced by the respective effects in the passivation layer.
  • the metal (M) represented by the general formula (I) is heat-treated (fired) in a state where the compound represented by the general formula (I) and the compound represented by the general formula (II) coexist.
  • the composite metal alkoxide of aluminum and aluminum (Al) the physical properties such as reactivity and vapor pressure are improved, the denseness of the passivation layer as a heat-treated product (baked product) is improved, and as a result, the passivation effect becomes higher. Conceivable.
  • each R 2 independently represents an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms.
  • the alkyl group represented by R 2 may be linear or branched. Specific examples of the alkyl group represented by R 2 include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, hexyl, octyl, 2- An ethylhexyl group etc. can be mentioned.
  • the alkyl group represented by R 2 is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms from the viewpoint of storage stability and a passivation effect, and is an unsubstituted alkyl group having 1 to 4 carbon atoms. More preferably.
  • n represents an integer of 0 to 3. n is preferably an integer of 1 to 3 and more preferably 1 or 3 from the viewpoint of storage stability.
  • X 2 and X 3 each independently represent an oxygen atom or a methylene group. From the viewpoint of storage stability, at least one of X 2 and X 3 is preferably an oxygen atom.
  • R 3 , R 4 and R 5 in the general formula (II) each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
  • the alkyl group represented by R 3 , R 4 and R 5 may be linear or branched.
  • the alkyl group represented by R 3 , R 4 and R 5 may have a substituent or may be unsubstituted, and is preferably unsubstituted.
  • the alkyl group represented by R 3 , R 4 and R 5 is an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms.
  • alkyl group represented by R 3 , R 4 and R 5 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, and a hexyl group.
  • R 3 and R 4 in the general formula (II) are preferably each independently a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms. Or it is more preferably an unsubstituted alkyl group having 1 to 4 carbon atoms.
  • R 5 in the general formula (II) is preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms from the viewpoint of storage stability and a passivation effect, and is preferably a hydrogen atom or a carbon atom having 1 to 4 carbon atoms. It is more preferably an unsubstituted alkyl group.
  • the compound represented by the general formula (II) is a compound in which n is 1 to 3, and R 5 is each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Preferably there is.
  • the compound represented by the general formula (II) is a compound in which n is 0 and R 2 is each independently an alkyl group having 1 to 4 carbon atoms from the viewpoint of storage stability and a passivation effect, and n Are 1 to 3, R 2 is independently an alkyl group having 1 to 4 carbon atoms, at least one of X 2 and X 3 is an oxygen atom, and R 3 and R 4 are each independently hydrogen It is preferably at least one selected from the group consisting of compounds that are an atom or an alkyl group having 1 to 4 carbon atoms, and R 5 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
  • R 2 is each independently an unsubstituted alkyl group having 1 to 4 carbon atoms
  • n is 1 to 3
  • R 2 is each independently an unsubstituted alkyl group having 1 to 4 carbon atoms
  • at least one of X 2 and X 3 is an oxygen atom
  • R 3 or R 4 bonded to the oxygen atom is A group consisting of a compound having a C 1-4 alkyl group, and when X 2 or X 3 is a methylene group, R 3 or R 4 bonded to the methylene group is a hydrogen atom
  • R 5 is a hydrogen atom It is at least 1 sort chosen from more.
  • Specific examples of the specific organoaluminum compound (aluminum trialkoxide) in which n is 0 in the general formula (II) include trimethoxyaluminum, triethoxyaluminum, triisopropoxyaluminum, trisec-butoxyaluminum, monosec-butoxy- Examples thereof include diisopropoxyaluminum, tri-t-butoxyaluminum, and tri-n-butoxyaluminum.
  • Specific examples of the specific organoaluminum compound in which n is 1 to 3 in the general formula (II) include aluminum ethylacetoacetate diisopropylate [(ethylacetoacetate) aluminum isopropoxide)], tris (ethylacetoacetate). Tato) aluminum and the like.
  • n 1 to 3 in the general formula (II)
  • a prepared product or a commercially available product may be used as the specific organoaluminum compound in which n is 1 to 3 in the general formula (II).
  • commercially available products include Kawaken Fine Chemical Co., Ltd. trade names, ALCH, ALCH-50F, ALCH-75, ALCH-TR, ALCH-TR-20, and the like.
  • the specific organoaluminum compound in which n is 1 to 3 in the general formula (II) can be prepared by mixing an aluminum trialkoxide and the compound having a specific structure having the two carbonyl groups described above.
  • Examples of the compound having a specific structure having two carbonyl groups include the above-mentioned ⁇ -diketone compound, ⁇ -ketoester compound, malonic acid diester and the like. From the viewpoint of storage stability, ⁇ -diketone compound, ⁇ -ketoester compound and It is preferably at least one selected from the group consisting of malonic acid diesters.
  • the number of aluminum chelate structures is not particularly limited as long as it is 1 to 3. Among these, 1 or 3 is preferable from the viewpoint of storage stability, and 1 is more preferable from the viewpoint of solubility.
  • the number of aluminum chelate structures can be controlled, for example, by appropriately adjusting the ratio of mixing aluminum trialkoxide and a compound having a specific structure having two carbonyl groups. Moreover, you may select suitably the compound which has a desired structure from a commercially available aluminum chelate compound.
  • the compounds represented by the general formula (II) from the viewpoint of the passivation effect and the compatibility with the solvent contained as necessary, specifically, it consists of aluminum ethyl acetoacetate diisopropylate and triisopropoxyaluminum. It is preferable to use at least one selected from the group, and it is more preferable to use aluminum ethyl acetoacetate diisopropylate.
  • the presence of the aluminum chelate structure in the specific organoaluminum compound can be confirmed by a commonly used analytical method, for example, using an infrared spectrum, a nuclear magnetic resonance spectrum, or a melting point.
  • the specific organoaluminum compound may be liquid or solid, and is not particularly limited. From the viewpoint of the passivation effect and storage stability, a specific organoaluminum compound having favorable stability at room temperature (25 ° C.) and good solubility or dispersibility is preferable, and the specific organoaluminum stable when used as a solution or dispersion A compound is preferred. By using such a specific organoaluminum compound, the homogeneity of the formed passivation layer is further improved, and a desired passivation effect tends to be stably obtained.
  • the content of the specific organoaluminum compound is not particularly limited. Especially, it is preferable that the content rate of a specific organoaluminum compound when the total content rate of a compound of a formula (I) and a specific organoaluminum compound is 100 mass% is 0.5 to 80 mass%.
  • the content is more preferably no less than 75% by mass and even more preferably no less than 2% by mass and no greater than 70% by mass, and particularly preferably no less than 3% by mass and no greater than 70% by mass.
  • the storage stability of the composition for forming a passivation layer tends to be improved. Moreover, it exists in the tendency for the passivation effect to improve because the content rate of a specific organoaluminum compound shall be 80 mass% or less.
  • the content of the specific organoaluminum compound in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the content of the specific organoaluminum compound can be 1% by mass to 70% by mass in the composition for forming a passivation layer, and 3% by mass to 60% by mass. It is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 30% by mass.
  • the composition for forming a passivation layer of the present invention contains at least one (specific compound) selected from the group consisting of a fatty acid amide, a polyalkylene glycol compound and an organic filler.
  • the composition for forming a passivation layer of the present invention containing a specific compound has a reduced viscosity when applied to a semiconductor substrate, and an increased viscosity after being applied. Therefore, the passivation layer forming composition of the present invention can form a passivation layer having a desired shape by a simple method.
  • the composition layer which is a coating film of the composition for forming a passivation layer tends to be more uniform by including the specific compound. This is thought to be because entrainment of bubbles is suppressed by lowering the viscosity of the composition for forming a passivation layer when applying the composition for forming a passivation layer to a semiconductor substrate.
  • the content of the specific compound contained in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the content of the specific compound can be 0.01% by mass to 70% by mass in the composition for forming a passivation layer, and 0.01% by mass to 60% by mass.
  • the content is 0.01% by mass to 50% by mass.
  • the polyalkylene glycol compound in the present invention may be liquid or solid and is not particularly limited. From the viewpoints of the passivation effect and printability, polyalkylene glycol compounds having good stability at room temperature (25 ° C.) and good solubility or dispersibility are preferred. By using such a polyalkylene glycol compound, the uniformity of the formed passivation layer is further improved, and a desired passivation effect tends to be stably obtained.
  • the polyalkylene glycol compound preferably contains at least one selected from compounds represented by the following general formula (III).
  • R 6 and R 7 each independently represent a hydrogen atom or an alkyl group, and R 8 represents an alkylene group.
  • n is an arbitrary integer of 3 or more.
  • a plurality of R 8 may be the same or different.
  • n represents an integer of 3 or more. From the viewpoint of printability, n is preferably from 5 to 23000, more preferably from 10 to 11000, and even more preferably from 20 to 2300. When n is 3 or more, it tends to be easily adjusted to a viscosity suitable for printing while suppressing the content of the compound represented by formula (III) in the composition for forming a passivation layer. Moreover, there exists a tendency to suppress that the viscosity of the composition for passivation layer formation becomes high too much that n is 23000 or less.
  • R 6 and R 7 in the general formula (III) each independently represent a hydrogen atom or an alkyl group.
  • the alkyl group represented by R 6 and R 7 preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, still more preferably 1 or 2.
  • R 6 and R 7 are each independently a hydrogen atom, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group, hexyl group, octyl group And preferably an ethylhexyl group, more preferably a hydrogen atom, a methyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group or a t-butyl group, and a hydrogen atom, a methyl group or More preferably, it is an ethyl group.
  • R 8 in the general formula (III) represents an alkylene group.
  • the alkylene group represented by R 8 preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and still more preferably 1 to 3 carbon atoms.
  • R 8 is preferably an ethylene group, a propylene group, a hexylene group, an octylene group, a dodecylene group or a hexadecylene group, more preferably an ethylene group, a propylene group, a hexylene group or an octylene group, More preferably, it is a group or a propylene group.
  • Specific examples of the compound represented by the general formula (III) include polyethylene glycol, polypropylene glycol, polyethylene glycol monomethyl ether, poly (ethylene glycol-propylene glycol) copolymer, and the like.
  • polyethylene glycol is preferable.
  • polyethylene glycol By using polyethylene glycol, the printability of the composition for forming a passivation layer tends to be improved, and polyethylene glycol is easily available.
  • 1 type may be used independently, or the compound represented by 2 or more types of general formula (III) from which a structure differs may be used together. Moreover, you may use the compound represented by general formula (III) by copolymerizing with another specific compound.
  • the combination includes a combination of polyethylene glycol and polypropylene glycol, a combination of polyethylene glycol and polyethylene glycol monomethyl ether, and the like. .
  • the compound represented by the general formula (III) may be liquid or solid. From the viewpoint of the passivation effect of the formed passivation layer and the printability of the composition for forming a passivation layer, when the compound represented by the general formula (III) is a solid, it dissolves in a solvent at room temperature (25 ° C.). It is preferable that the compound has good properties or dispersibility, and it is preferable that the compound is stable when it is used as a solution or dispersion. In the case of such a compound, the homogeneity of the formed passivation layer is further improved, and a desired passivation effect can be stably obtained.
  • the glass transition temperature is not particularly limited and is preferably in the range of ⁇ 100 ° C. to 100 ° C., and in the range of ⁇ 50 ° C. to 25 ° C. It is more preferable that In the present invention, the glass transition temperature of the compound represented by the general formula (III) is determined by examining the mutation point of a differential scanning calorimetry (DSC) curve measured using a suggested thermal analyzer. It can be measured.
  • DSC differential scanning calorimetry
  • the melting point is not particularly limited and is preferably in the range of 20 ° C to 200 ° C, more preferably in the range of 40 ° C to 100 ° C. .
  • the melting point of the compound represented by the general formula (III) can be measured by examining a melting peak measured using a suggested thermal analyzer.
  • the number average molecular weight of the compound represented by the general formula (III) is preferably 1,000 to 5,000,000, and more preferably 2,000 to 5,000,000.
  • the number average molecular weight is 1000 or more, the functionality as a thixotropic agent is sufficiently exhibited, and when it is 5,000,000 or less, the viscosity of the composition for forming a passivation layer can be prevented from becoming too high. Therefore, the printability becomes better. Moreover, there exists a tendency for printability to become further favorable that it is 2,000 or more.
  • the number average molecular weight can be measured using gel permeation chromatography (GPC method). In addition, the measurement conditions of the number average molecular weight by GPC method are as follows, for example.
  • Measuring device Shodex GPC SYSTEM-11 (Showa Denko KK) Eluent: CF3COONa 5 mmol / hexafluoroisopropyl alcohol (HFIP) (1 liter) Column: Sample column HFIP-800P HFIP-80M x 2, Reference column HFIP-800R x 2 Column temperature: 40 ° C Flow rate: 1.0 ml / min Detector: Shodex RI STD: PMMA (Shodex STANDARD M-75)
  • the fatty acid amide is at least selected from the group consisting of a compound represented by the following general formula (1), a compound represented by (2), a compound represented by (3), and a compound represented by (4) It is preferable that 1 type is included. In addition, fatty acid amide may be used individually by 1 type, or may use 2 or more types together.
  • R 9 CONH 2 (1) R 9 CONH-R 10 -NHCOR 9 (2) R 9 NHCO—R 10 —CONHR 9 (3) R 9 CONH—R 10 —N (R 11 ) 2 ... (4)
  • R 9 and R 11 each independently represents an alkyl group or an alkenyl group having 2 to 30 carbon atoms having 1 to 30 carbon atoms
  • R 10 Represents an alkylene group having 1 to 10 carbon atoms.
  • a plurality of R 11 may be the same or different.
  • the alkyl group and alkenyl group represented by R 9 and R 11 may each independently be linear, branched or cyclic, and are preferably linear or branched.
  • the alkyl group and alkenyl group represented by R 9 and R 11 may be unsubstituted or may have a substituent.
  • substituents include a hydroxyl group, a chloro group, a bromo group, a fluoro group, an aldehyde group, a carbonyl group, a nitro group, an amine group, a sulfonic acid group, an alkoxy group, and an acyloxy group.
  • alkyl group and alkenyl group represented by R 9 and R 11 include a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, an isobutyl group, a decane group, a dodecane group, an octadecane group, and a hexadecenyl group. And henicosenyl group.
  • the alkyl group and alkenyl group represented by R 9 each independently preferably has 5 to 25 carbon atoms, more preferably 10 to 20 carbon atoms, and further preferably 15 to 18 carbon atoms. preferable.
  • the alkyl groups represented by R 11 each independently preferably have 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms.
  • Each of the alkenyl groups represented by R 11 preferably independently has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and still more preferably 2 to 3 carbon atoms.
  • R 9 is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms, An alkyl group of 1 to 3 is particularly preferable.
  • the alkylene group represented by R 10 is independently 2 to 10 carbon atoms, and from the viewpoint of printability and passivation effect, 2 to It is preferably 8, more preferably 2 to 6 carbon atoms, and still more preferably 2 to 4 carbon atoms.
  • the alkylene group represented by R 10 may be linear or branched.
  • Specific examples of the alkylene group represented by R 8 include an ethylene group, a propylene group, a butylene group, and an octylene group.
  • fatty acid monoamide represented by the general formula (1) examples include lauric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, erucic acid amide and the like.
  • N-substituted fatty acid amide represented by the general formula (2) examples include N, N′-ethylenebislauric acid amide, N, N′-methylenebisstearic acid amide, N, N′-ethylenebisamide.
  • Examples thereof include amide, N, N′-hexamethylenebisstearic acid amide, N, N′-hexamethylenebisoleic acid amide, N, N′-xylylene bisstearic acid amide, and the like.
  • N-substituted fatty acid amide represented by the general formula (3) examples include N, N′-dioleyl adipate amide, N, N′-distearyl adipate amide, N, N′-dioleyl.
  • Examples include sebacic acid amide, N, N′-distearyl sebacic acid amide, N, N′-distearyl terephthalic acid amide, N, N′-distearyl isophthalic acid amide, and the like.
  • N-substituted fatty acid amidoamine represented by the general formula (4) include stearic acid dimethylaminopropylamide, stearic acid diethylaminoethylamide, lauric acid dimethylaminopropylamide, myristic acid dimethylaminopropylamide, palmitic acid.
  • fatty acid amides at least one selected from the group consisting of stearic acid amide, N, N′-methylenebisstearic acid amide and stearic acid dimethylaminopropylamide is used from the viewpoint of solubility in a dispersion medium. It is preferable.
  • the fatty acid amide may be liquid or solid. From the viewpoint of the passivation effect and printability, when the fatty acid amide is a solid, it is preferably a compound that has good solubility or dispersibility at room temperature (25 ° C.) with respect to the solvent. Sometimes a stable compound is preferred. In the case of such a compound, the homogeneity of the formed passivation layer is further improved, and a desired passivation effect can be stably obtained.
  • the fatty acid amide is desirably evaporated or decomposed at 30 to 400 ° C., more preferably evaporated or decomposed at 40 to 300 ° C., and further desirably evaporated or decomposed at 50 to 250 ° C. or less. It is preferable that the fatty acid amide evaporates or disperses at 400 ° C. or lower because it does not inhibit the formation of the passivation layer.
  • preferred compounds include polyethylene glycol and polypropylene glycol from the viewpoint of printability and solubility in a dispersion medium.
  • Stearic acid amide, N, N′-methylenebisstearic acid amide and stearic acid dimethylaminopropylamide are preferably used, and at least one selected from polyethylene glycol and stearic acid amide is preferably used. It is more preferable.
  • Organic filler is preferably a particle or a fibrous material composed of an organic compound.
  • Organic filler materials include urea formalin resin, phenol resin, polycarbonate resin, melamine resin, epoxy resin, unsaturated polyester resin, silicone resin, polyurethane resin, polyolefin resin, acrylic resin, fluorine resin, polystyrene resin, cellulose resin, formaldehyde Examples thereof include resins, coumarone indene resins, lignin resins, petroleum resins, amino resins, polyester resins, polyether sulfone resins, butadiene resins, and copolymers thereof.
  • An organic filler is used individually by 1 type or in combination of 2 or more types.
  • the material of the organic filler is preferably at least one selected from the group consisting of an acrylic resin, a cellulose resin, and a polystyrene resin from the viewpoint of thermal decomposability, and more preferably an acrylic resin.
  • the monomers constituting the acrylic resin include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, acrylic acid n-butyl, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, pentyl acrylate, pentyl methacrylate, Hexyl acrylate, hexyl methacrylate, heptyl acrylate, heptyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, octyl acrylate, oc
  • the organic filler is solid in the liquid medium.
  • the organic filler is preferably an organic filler that has good dispersibility at room temperature (25 ° C.) with respect to a liquid medium, and is preferably an organic filler that is stable when used as a dispersion.
  • the uniformity of the formed passivation layer is further improved, and a desired passivation effect can be stably obtained.
  • the organic filler preferably decomposes at 30 to 400 ° C, more preferably has a decomposition temperature of 40 to 300 ° C, and still more preferably 50 to 250 ° C.
  • a composition layer is formed from the composition for forming a passivation layer, and the composition layer is subjected to a heat treatment (firing) to form a passivation layer. Is preferable.
  • the decomposition temperature can be measured with a thermogravimetric analyzer (Shimadzu Corporation, DTG-60H). Moreover, the decomposition temperature here means the temperature at which the substance begins to lose weight due to the influence of heat.
  • the volume average particle diameter is preferably 10 ⁇ m or less, more preferably 1 ⁇ m or less, and further preferably 0.1 ⁇ m or less.
  • the volume average particle size is 10 ⁇ m or less, there is a tendency that a greater thixotropy can be obtained with a small amount of addition.
  • a screen printing method is used as a method for applying the composition for forming a passivation layer, clogging of the mesh of the printing mask can be suppressed.
  • the volume average particle diameter of the organic filler can be measured by a laser diffraction scattering particle size distribution measuring apparatus (for example, Beckman Coulter LS13320), and the value obtained by calculating the median diameter from the obtained particle size distribution is defined as the average particle diameter. be able to. Moreover, an average particle diameter can also be calculated
  • the content of the specific compound contained in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the composition for forming a passivation layer may be 0.01% by mass to 70% by mass, preferably 0.01% by mass to 60% by mass, More preferably, the content is 0.01% by mass to 50% by mass.
  • the composition for forming a passivation layer may further contain at least one resin.
  • the shape stability of the composition layer formed by applying the composition for forming the passivation layer on the semiconductor substrate is further improved, and the passivation layer is formed in a desired region in the region where the composition layer is formed. It can be selectively formed by shape.
  • the type of resin is not particularly limited. Among these, when the composition for forming a passivation layer is applied on a semiconductor substrate, a resin capable of adjusting the viscosity within a range in which a good pattern can be formed is preferable.
  • the resin include polyvinyl alcohol, polyacrylamide, polyacrylamide derivatives, polyvinyl amide, polyvinyl amide derivatives, polyvinyl pyrrolidone, polyethylene oxide, polyethylene oxide derivatives, polysulfonic acid, acrylamide alkyl sulfonic acid, cellulose, cellulose derivatives (carboxymethyl cellulose, Hydroxyethyl cellulose, cellulose ethers such as ethyl cellulose), gelatin, gelatin derivatives, starch, starch derivatives, sodium alginate, sodium alginate derivatives, xanthan, xanthan derivatives, guar gum, guar gum derivatives, scleroglucan, scleroglucan derivatives, tragacanth,
  • (meth) acrylic acid means at least one of “acrylic acid” and “methacrylic acid”
  • (meth) acrylate means at least one of “acrylate” and “methacrylate”. means.
  • the molecular weight of these resins is not particularly limited, and it is preferable to adjust appropriately in view of the desired viscosity as the composition for forming a passivation layer.
  • the weight average molecular weight of the resin is preferably from 100 to 10,000,000, more preferably from 1,000 to 5,000,000, from the viewpoints of storage stability and pattern formability.
  • the weight average molecular weight of resin is calculated
  • the molecular weight of the resin is measured under the same measurement conditions as those for the compound represented by the general formula (III).
  • the content of the resin in the composition for forming a passivation layer can be appropriately selected as necessary.
  • the content of the resin in the composition for forming a passivation layer is preferably 0.1% by mass to 50% by mass. From the viewpoint of expressing thixotropy that facilitates pattern formation, the content is preferably 0.2% by mass to 25% by mass, and more preferably 0.5% by mass to 20% by mass. More preferably, the content is 0.5 to 15% by mass.
  • the composition for forming a passivation layer contains a resin
  • the compound of formula (I) in the composition for forming a passivation layer when further containing a specific organoaluminum compound, the total amount of the compound of formula (I) and the specific organoaluminum compound)
  • the content ratio (mass ratio) of the resin can be appropriately selected as necessary.
  • the content ratio of the resin to the compound of the formula (I) (resin / the compound of the formula (I)), and further containing the specific organoaluminum compound, the compound of the formula (I) is preferably 0.001 to 1000, and preferably 0.01 to 100. More preferably, it is 0.1 to 1.
  • the composition for forming a passivation layer may further contain a liquid medium (solvent or dispersion medium).
  • a liquid medium solvent or dispersion medium
  • the viscosity can be easily adjusted, the impartability is further improved, and a more uniform passivation layer tends to be formed.
  • the liquid medium is not particularly limited and can be appropriately selected as necessary. Among them, a liquid medium capable of obtaining a uniform solution or dispersion by dissolving the compound of formula (I) and the specific organoaluminum compound used as necessary, a resin or the like is preferable, and includes at least one organic solvent. Is more preferable.
  • liquid medium examples include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isopropyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, methyl-n-pentyl ketone, methyl-n-hexyl ketone, diethyl ketone, Ketone solvents such as dipropyl ketone, diisobutyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone; diethyl ether, methyl ethyl ether, methyl-n-propyl ether, diisopropyl Ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether
  • Aprotic polar solvents such as methylene chloride, chloroform, dichloroethane, benzene, toluene, xylene, hexane, octane, ethylbenzene, 2-ethylhexanoic acid, methyl isobutyl ketone, methyl ethyl ketone; methanol, ethanol, n-propanol , Isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, n-pentanol, isopentanol, 2-methylbutanol, sec-pentano , T-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n-oct
  • the liquid medium preferably contains at least one selected from the group consisting of a terpene solvent, an ester solvent, and an alcohol solvent, and is selected from the group consisting of a terpene solvent, from the viewpoint of impartability to a semiconductor substrate and pattern formation. More preferably, at least one kind is included.
  • a liquid medium having a high viscosity and a low boiling point (high viscosity, low boiling point solvent) may be used.
  • the composition for forming a passivation layer containing a high-viscosity low-boiling solvent has a viscosity that can sufficiently maintain the shape of the composition layer formed by applying it to a semiconductor substrate, and volatilizes during the subsequent heat treatment (firing) step. There is an advantage that the influence of the residual solvent can be suppressed.
  • Specific examples of the high-viscosity low-boiling solvent include isobornylcyclohexanol.
  • Isobornylcyclohexanol is commercially available as “Telsolve MTPH” (Nippon Terpene Chemical Co., Ltd., trade name). Isobornyl cyclohexanol has a high boiling point of 308 ° C. to 318 ° C. When it is removed from the composition layer, it does not need to be degreased by heat treatment (firing) like a resin, but is vaporized by heating. Can be eliminated. For this reason, most of the solvent and isobornyl cyclohexanol contained in the composition for forming a passivation layer as necessary can be removed in the drying step after application on the semiconductor substrate.
  • the content of the high-viscosity low-boiling solvent is preferably 3% by mass to 95% by mass in the total mass of the composition for forming a passivation layer. It is more preferably 5% by mass to 90% by mass, and particularly preferably 7% by mass to 80% by mass.
  • the content of the liquid medium is determined in consideration of applicability, pattern formability, and storage stability.
  • the content of the liquid medium is preferably 5% by mass to 98% by mass in the composition for forming a passivation layer, from the viewpoint of the impartability of the composition and the pattern formability, and 10% by mass to 95% by mass. It is more preferable that
  • the composition for forming a passivation layer may contain an acidic compound or a basic compound.
  • the content of the acidic compound and the basic compound is 1% by mass or less in the composition for forming a passivation layer, respectively. It is preferable that it is 0.1 mass% or less.
  • Examples of acidic compounds include Bronsted acid and Lewis acid. Specific examples include inorganic acids such as hydrochloric acid and nitric acid, and organic acids such as acetic acid.
  • Examples of basic compounds include Bronsted bases and Lewis bases. Specifically, examples of basic compounds include inorganic bases such as alkali metal hydroxides and alkaline earth metal hydroxides, and trialkyls. Examples thereof include organic bases such as amine and pyridine.
  • the composition for forming a passivation layer may contain at least one oxide selected from the group consisting of Nb, Ta, V, Y, and Hf (hereinafter referred to as “specific oxide”). Since the specific oxide is an oxide generated by heat-treating (sintering) the compound of formula (I), the passivation layer formed from the composition for forming a passivation layer containing the specific oxide has an excellent passivation effect. Is expected to be played.
  • the composition for forming a passivation layer may further contain aluminum oxide (Al 2 O 3 ). Aluminum oxide is an oxide produced by heat-treating (firing) a compound represented by the formula (II). Therefore, the composition for forming a passivation layer containing the compound of formula (I) and aluminum oxide is expected to exhibit an excellent passivation effect.
  • the viscosity of the composition for forming a passivation layer is not particularly limited, and can be appropriately selected depending on a method for applying the composition to a semiconductor substrate.
  • the viscosity of the composition for forming a passivation layer can be 0.01 Pa ⁇ s to 10,000 Pa ⁇ s.
  • the viscosity of the composition for forming a passivation layer is preferably 0.1 Pa ⁇ s to 1000 Pa ⁇ s.
  • the viscosity is measured using a rotary shear viscometer at 25 ° C. and a shear rate of 1.0 s ⁇ 1 .
  • the shear viscosity of the composition for forming a passivation layer is not particularly limited, and it is preferable that the composition for forming a passivation layer has thixotropy.
  • thixotropic ratio calculated by dividing the shear viscosity eta 1 at shear viscosity eta 2 at a shear rate of 10s -1 at a shear rate of 1.0s -1 ( ⁇ 1 / ⁇ 2 ) is 1. It is preferably from 05 to 100, more preferably from 1.1 to 50.
  • the shear viscosity is measured at a temperature of 25 ° C. using a rotary shear viscometer equipped with a cone plate (diameter 50 mm, cone angle 1 °).
  • the components contained in the composition for forming a passivation layer and the content of each component are determined by thermal analysis such as differential thermal-thermogravimetric simultaneous measurement (TG / DTA), nuclear magnetic resonance (NMR), infrared spectroscopy ( It can be confirmed by spectral analysis such as IR), chromatographic analysis such as high performance liquid chromatography (HPLC), gel permeation chromatography (GPC) and the like.
  • thermal analysis such as differential thermal-thermogravimetric simultaneous measurement (TG / DTA), nuclear magnetic resonance (NMR), infrared spectroscopy ( It can be confirmed by spectral analysis such as IR), chromatographic analysis such as high performance liquid chromatography (HPLC), gel permeation chromatography (GPC) and the like.
  • the compound represented by the general formula (I) there is no restriction
  • the compound represented by the general formula (I) at least one selected from fatty acid amides, polyalkylene glycol compounds and organic fillers, and a liquid medium or the like contained as needed are usually mixed. It can manufacture by mixing with.
  • at least one selected from a fatty acid amide, a polyalkylene glycol compound and an organic filler may be dissolved in a liquid medium and then mixed with the compound represented by the general formula (I). .
  • the compound represented by the general formula (I) may be prepared by mixing a metal alkoxide contained in the compound of the formula (I) with a compound capable of forming a chelate with the metal. At that time, a liquid medium may be used as necessary, or heat treatment may be performed.
  • a composition for forming a passivation layer is produced by mixing the compound of formula (I) thus prepared and a solution or dispersion containing at least one selected from fatty acid amides, polyalkylene glycol compounds and organic fillers. May be.
  • the semiconductor substrate with a passivation layer of the present invention includes a semiconductor substrate and a passivation layer that is a heat treatment product (baked product) of the composition for forming a passivation layer provided on the entire surface or a part of the semiconductor substrate.
  • the semiconductor substrate with a passivation layer exhibits an excellent passivation effect by having a passivation layer that is a heat-treated product layer (baked product layer) of the composition for forming a passivation layer.
  • the semiconductor substrate is not particularly limited, and can be appropriately selected from those usually used according to the purpose.
  • Examples of the semiconductor substrate include those obtained by doping (diffusing) p-type impurities or n-type impurities into silicon, germanium, or the like. Of these, a silicon substrate is preferable.
  • the semiconductor substrate may be a p-type semiconductor substrate or an n-type semiconductor substrate. Among these, from the viewpoint of the passivation effect, it is preferable that the surface on which the passivation layer is formed is a semiconductor substrate having a p-type layer.
  • the p-type layer on the semiconductor substrate is a p-type layer derived from the p-type semiconductor substrate
  • the p-type layer is formed on the n-type semiconductor substrate or the p-type semiconductor substrate as a p-type diffusion layer or a p + -type diffusion layer. It may be a thing.
  • the thickness of the semiconductor substrate is not particularly limited and can be appropriately selected according to the purpose.
  • the thickness of the semiconductor substrate can be 50 ⁇ m to 1000 ⁇ m, preferably 75 ⁇ m to 750 ⁇ m.
  • the thickness of the passivation layer formed on the semiconductor substrate is not particularly limited and can be appropriately selected depending on the purpose.
  • the thickness of the passivation layer is preferably 5 nm to 50 ⁇ m, more preferably 10 nm to 30 ⁇ m, and still more preferably 15 nm to 20 ⁇ m.
  • the semiconductor substrate with a passivation layer can be applied to solar cell elements, light emitting diode elements, and the like.
  • the solar cell element excellent in conversion efficiency can be obtained by applying to a solar cell element.
  • the method for producing a semiconductor substrate with a passivation layer according to the present invention includes a step of forming the composition layer by applying the composition for forming a passivation layer on the entire surface or a part of the semiconductor substrate, and heat-treating the composition layer ( Firing) to form a passivation layer.
  • the manufacturing method may further include other steps as necessary.
  • the method for producing a semiconductor substrate with a passivation layer preferably further includes a step of applying an alkaline aqueous solution on the semiconductor substrate before the step of forming the composition layer. That is, it is preferable to wash the surface of the semiconductor substrate with an alkaline aqueous solution before applying the composition for forming a passivation layer on the semiconductor substrate. By washing with an alkaline aqueous solution, organic substances, particles, and the like present on the surface of the semiconductor substrate can be removed, and the passivation effect is further improved.
  • a method for cleaning with an alkaline aqueous solution generally known RCA cleaning and the like can be exemplified.
  • the semiconductor substrate is immersed in a mixed solution of ammonia water and hydrogen peroxide solution and treated at 60 ° C. to 80 ° C., thereby removing organic substances and particles and washing the semiconductor substrate.
  • the washing time is preferably 10 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes.
  • a method for forming a composition layer by applying a passivation layer forming composition on a semiconductor substrate For example, a method for applying a composition for forming a passivation layer on a semiconductor substrate using a known application method or the like can be mentioned. Specific examples include immersion method, printing, dispenser method, spin coating method, brush coating, spraying method, doctor blade method, roll coating method, and ink jet method. Among these, from the viewpoint of pattern formability, various printing methods (for example, screen printing), inkjet methods, and the like are preferable.
  • the composition for forming a passivation layer of the present invention is excellent in printability and coating film uniformity even when applied to a printing method.
  • the application amount of the composition for forming a passivation layer can be appropriately selected according to the purpose.
  • the thickness of the passivation layer to be formed can be appropriately adjusted so as to be a desired thickness described later.
  • a passivation layer is formed on a semiconductor substrate by heat-treating (baking) the composition layer formed by the composition for forming a passivation layer to form a heat-treated material layer (baked material layer) derived from the composition layer.
  • the heat treatment (firing) condition of the composition layer is a heat treated product (firing product) of the compound represented by the formula (I) contained in the composition layer and the compound represented by the general formula (II) contained as necessary.
  • the heat treatment (firing) conditions that can form an amorphous metal oxide layer are preferable.
  • the passivation layer When the passivation layer is composed of an amorphous metal oxide layer, the passivation layer can effectively have a negative charge, and a more excellent passivation effect can be obtained.
  • the heat treatment (firing) temperature is preferably 400 ° C. to 900 ° C., more preferably 450 ° C. to 800 ° C.
  • the heat treatment (firing) temperature here means the maximum temperature in the furnace used for the heat treatment (firing).
  • the heat treatment (firing) time can be appropriately selected according to the heat treatment (firing) temperature and the like. For example, it can be within 10 hours, preferably within 5 hours.
  • the heat treatment (firing) time here means the holding time at the maximum temperature.
  • the heat treatment (firing) can be performed using a diffusion furnace (for example, ACCURONUCQ-1200, DD-200P, both of which are Hitachi Kokusai Electric; 206A-M100, Koyo Thermo System Co., Ltd.).
  • the atmosphere in which the heat treatment (firing) is performed is not particularly limited, and can be performed in the air.
  • the thickness of the passivation layer produced by the method for producing a semiconductor substrate with a passivation layer is not particularly limited and can be appropriately selected according to the purpose.
  • the average thickness of the passivation layer is preferably 5 nm to 50 ⁇ m, more preferably 10 nm to 30 ⁇ m, and still more preferably 15 nm to 20 ⁇ m.
  • the average thickness of the formed passivation layer is calculated as the arithmetic average value by measuring the thickness at three points by a conventional method using a stylus type step / surface shape measuring device (for example, Ambios). .
  • a method of manufacturing a semiconductor substrate with a passivation layer includes: a composition layer comprising a composition for forming a passivation layer, after the composition for forming a passivation layer is applied to the semiconductor substrate and before the step of forming the passivation layer by heat treatment (firing). You may further have the process of drying-processing. By having a step of drying the composition layer, a passivation layer having a more uniform passivation effect can be formed.
  • the step of drying the composition layer is not particularly limited as long as at least a part of the liquid medium that may be contained in the passivation layer forming composition can be removed.
  • the drying treatment can be, for example, a heat treatment at 30 ° C. to 250 ° C. for 1 minute to 60 minutes, and is preferably a heat treatment at 40 ° C. to 220 ° C. for 3 minutes to 40 minutes.
  • the drying treatment may be performed under normal pressure or under reduced pressure.
  • the method for producing a semiconductor substrate with a passivation layer includes the step of forming a passivation layer after applying the composition for forming a passivation layer and before forming the passivation layer by heat treatment (firing). You may further have the process of degreasing the composition layer which consists of a composition for formation. By having a step of degreasing the composition layer, a passivation layer having a more uniform passivation effect can be formed.
  • the step of degreasing the composition layer is not particularly limited as long as at least part of the resin that may be contained in the composition for forming a passivation layer can be removed.
  • the degreasing treatment can be, for example, a heat treatment at 250 to 450 ° C. for 10 to 120 minutes, preferably a heat treatment at 300 to 400 ° C. for 3 to 60 minutes.
  • the degreasing treatment is preferably performed in the presence of oxygen, and more preferably performed in the air.
  • the solar cell element of the present invention includes a semiconductor substrate in which a p-type layer and an n-type layer are pn-junction, and a heat treatment product (baked product) of the passivation layer forming composition provided on the entire surface or a part of the semiconductor substrate. ) And an electrode disposed on one or more layers selected from the group consisting of the p-type layer and the n-type layer.
  • the solar cell element may further include other components as necessary.
  • a solar cell element is excellent in conversion efficiency by having the passivation layer formed from the composition for passivation layer formation of this invention.
  • the semiconductor substrate to which the composition for forming a passivation layer is applied is not particularly limited, and can be appropriately selected from those usually used according to the purpose.
  • a semiconductor substrate what was demonstrated by the semiconductor substrate with a passivation layer can be used, and the thing which can be used conveniently is also the same.
  • the surface of the semiconductor substrate on which the passivation layer is provided is preferably a p-type layer.
  • the thickness of the passivation layer formed on the semiconductor substrate is not particularly limited and can be appropriately selected depending on the purpose.
  • the average thickness of the passivation layer is preferably 5 nm to 50 ⁇ m, more preferably 10 nm to 30 ⁇ m, and still more preferably 15 nm to 20 ⁇ m.
  • the method for manufacturing a solar cell element of the present invention has a pn junction formed by joining a p-type layer and an n-type layer, and is on one or more layers selected from the group consisting of the p-type layer and the n-type layer
  • a step of forming the composition layer by applying the composition for forming a passivation layer on one or both of the surfaces having the electrodes of a semiconductor substrate having electrodes on the substrate, and heat-treating (firing) the composition layer
  • a step of forming a passivation layer may further include other steps as necessary.
  • a solar cell element having a passivation layer having an excellent passivation effect and excellent in conversion efficiency can be produced by a simple method. Further, a passivation layer can be formed on the semiconductor substrate on which the electrode is formed so as to have a desired shape, and the productivity of the solar cell element is excellent.
  • a semiconductor substrate having a pn junction in which an electrode is disposed on at least one of a p-type layer and an n-type layer can be manufactured by a commonly used method. For example, it can be manufactured by applying an electrode forming paste such as a silver paste or an aluminum paste to a desired region of a semiconductor substrate and performing a heat treatment (firing) as necessary.
  • an electrode forming paste such as a silver paste or an aluminum paste
  • the surface of the semiconductor substrate on which the passivation layer is provided may be a p-type layer or an n-type layer. Among these, a p-type layer is preferable from the viewpoint of conversion efficiency.
  • the details of the method for forming a passivation layer using the composition for forming a passivation layer are the same as the method for manufacturing a semiconductor substrate with a passivation layer described above, and the preferred embodiments are also the same.
  • the thickness of the passivation layer formed on the semiconductor substrate is not particularly limited and can be appropriately selected according to the purpose.
  • the average thickness of the passivation layer is preferably 5 nm to 50 ⁇ m, more preferably 10 nm to 30 ⁇ m, and still more preferably 15 nm to 20 ⁇ m.
  • FIG. 1 is a sectional view schematically showing an example of a method for producing a solar cell element having a passivation layer according to this embodiment.
  • this process diagram does not limit the present invention at all.
  • an n + -type diffusion layer 2 is formed in the vicinity of the surface, and an antireflection film 3 is formed on the outermost surface.
  • the antireflection film 3 include a silicon nitride film and a titanium oxide film.
  • a surface protective film such as silicon oxide may further exist between the antireflection film 3 and the p-type semiconductor substrate 1.
  • a material for forming the back electrode 5 such as an aluminum electrode paste is applied to a part of the back surface, and then heat-treated (fired) to form the back electrode 5, and p A p + type diffusion layer 4 is formed by diffusing aluminum atoms in the type semiconductor substrate 1.
  • the electrode-forming paste is applied to the light-receiving surface side, and then heat-treated (fired) to form the light-receiving surface electrode 7.
  • those containing glass powder having a fire-through property as an electrode forming paste, reaches through the antireflective film 3, as shown in FIG. 1 (c), on the n + -type diffusion layer 2, the light-receiving surface
  • the electrode 7 can be formed to obtain an ohmic contact.
  • the composition for passivation layer formation is provided by screen printing etc. on the p-type layer of the back surface other than the area
  • the passivation layer 6 is formed by heat-treating (baking) the composition layer formed on the p-type layer.
  • the back electrode formed of aluminum or the like can have a point contact structure, and the warpage of the substrate can be reduced. Furthermore, by using the composition for forming a passivation layer, the passivation layer can be formed with excellent productivity at a specific position (specifically, on the p-type layer other than the region where the electrode is formed).
  • FIG. 1D shows a method of forming a passivation layer only on the back surface portion.
  • a passivation layer forming composition is applied to the side surface, and this is subjected to heat treatment.
  • the passivation layer 6 may be further formed on the side surface (edge) of the semiconductor substrate 1 by (baking) (not shown). Thereby, the solar cell element excellent in power generation efficiency can be manufactured.
  • the passivation layer 6 may be formed by forming the passivation layer forming composition of the present invention only on the side surface without forming the passivation layer on the back surface portion, and performing heat treatment (firing). When the composition for forming a passivation layer of the present invention is used in a portion having many crystal defects such as side surfaces, the effect is particularly great.
  • FIG. 1 illustrates an embodiment in which a passivation layer is formed after electrode formation
  • an electrode such as aluminum may be further formed in a desired region by vapor deposition or the like after formation of the passivation layer.
  • FIG. 2 is a cross-sectional view schematically showing another process example of a method for manufacturing a solar cell element having a passivation layer according to the present embodiment.
  • FIG. 2 shows the heat treatment of the aluminum electrode paste after forming the p + type diffusion layer using the aluminum electrode paste or the p type diffusion layer forming composition capable of forming the p + type diffusion layer by thermal diffusion treatment.
  • the process drawing including the process of removing the heat-treated product of the product or the p + -type diffusion layer forming composition will be described as a cross-sectional view.
  • the p-type diffusion layer forming composition include a composition containing an acceptor element-containing substance and a glass component.
  • an n + -type diffusion layer 2 is formed in the vicinity of the surface of the p-type semiconductor substrate 1, and an antireflection film 3 is formed on the surface.
  • the antireflection film 3 include a silicon nitride film and a titanium oxide film.
  • the p + -type diffusion layer 4 is formed by applying a p-type diffusion layer forming composition to a partial region of the back surface and then performing heat treatment.
  • a heat treatment product 8 of a composition for forming a p type diffusion layer is formed on the p + type diffusion layer 4.
  • an aluminum electrode paste may be used instead of the p-type diffusion layer forming composition.
  • an aluminum electrode 8 is formed on the p + type diffusion layer 4.
  • the heat-treated product 8 or the aluminum electrode 8 of the p-type diffusion layer forming composition formed on the p + -type diffusion layer 4 is removed by a technique such as etching.
  • the electrode forming paste is selectively applied to the light receiving surface (front surface) and a part of the back surface, and then heat-treated, and the light receiving surface electrode 7 is applied to the light receiving surface (front surface).
  • the back electrode 5 is formed on the back surface.
  • the antireflection film 3 is penetrated to form an n + type diffusion layer.
  • the light-receiving surface electrode 7 is formed on the surface 2 and an ohmic contact can be obtained.
  • the electrode forming paste for forming the back electrode 5 is not limited to the aluminum electrode paste, but may be a silver electrode paste or the like. An electrode paste capable of forming a lower resistance electrode can also be used. As a result, the power generation efficiency can be further increased.
  • the composition for passivation layer formation is provided on the p-type layer of the back surface other than the area
  • the application can be performed by a method such as screen printing.
  • the passivation layer 6 is formed by heat-treating (firing) the composition layer formed on the p + -type diffusion layer 4.
  • FIG. 2E shows a method of forming a passivation layer only on the back surface portion.
  • a passivation layer material is also applied to the side surface, and heat treatment (firing) is performed.
  • a passivation layer may be further formed on the side surface (edge) of the p-type semiconductor substrate 1 (not shown).
  • the passivation layer may be formed by applying the composition for forming a passivation layer of the present invention only to the side surface without forming the passivation layer on the back surface portion, and heat-treating (firing) the composition.
  • the composition for forming a passivation layer of the present invention is used in a portion having many crystal defects such as side surfaces, the effect is particularly great.
  • an electrode such as aluminum may be further formed in a desired region by vapor deposition or the like.
  • a p-type semiconductor substrate having an n + -type diffusion layer formed on the light-receiving surface has been described.
  • an n-type semiconductor substrate having a p + -type diffusion layer formed on the light-receiving surface is described.
  • a solar cell element can be produced.
  • an n + type diffusion layer is formed on the back side.
  • the composition for forming a passivation layer can also be used to form a passivation layer 6 on the light receiving surface side or the back surface side of a back electrode type solar cell element in which an electrode is disposed only on the back surface side as shown in FIG.
  • a passivation layer 6 and an antireflection film 3 are formed on the surface.
  • the antireflection film 3 a silicon nitride film, a titanium oxide film, or the like is known.
  • the passivation layer 6 is formed by applying the passivation layer forming composition of the present invention and heat-treating (firing) it.
  • a back electrode 5 is provided on each of the p + -type diffusion layer 4 and the n + -type diffusion layer 2, and a passivation layer 6 is provided in a region where no back-side electrode is formed.
  • the p + -type diffusion layer 4 can be formed by applying a heat treatment after applying the p-type diffusion layer forming composition or the aluminum electrode paste to a desired region as described above.
  • the n + -type diffusion layer 2 can be formed by, for example, applying a composition for forming an n-type diffusion layer capable of forming an n + -type diffusion layer to a desired region by heat diffusion treatment and then performing a heat treatment. Examples of the composition for forming an n-type diffusion layer include a composition containing a donor element-containing material and a glass component.
  • the back electrode 5 provided on each of the p + type diffusion layer 4 and the n + type diffusion layer 2 can be formed using a commonly used electrode forming paste such as a silver electrode paste.
  • the back electrode 5 provided on the p + -type diffusion layer 4 may be an aluminum electrode formed with the p + -type diffusion layer 4 using aluminum electrode paste.
  • the passivation layer 6 provided on the back surface can be formed by applying a composition for forming a passivation layer to a region where the back electrode 5 is not provided and heat-treating (baking) the composition. Further, the passivation layer 6 may be formed not only on the back surface of the p-type semiconductor substrate 1 but also on the side surface (not shown).
  • the power generation efficiency is excellent. Furthermore, since the passivation layer is formed in the region where the back electrode is not formed, the conversion efficiency is further improved.
  • the solar cell includes the solar cell element and a wiring material provided on the electrode of the solar cell element. If necessary, the solar cell may be constituted by connecting a plurality of solar cell elements via a wiring material such as a tab wire and further sealing with a sealing material.
  • the wiring material and the sealing material are not particularly limited, and can be appropriately selected from those usually used in the industry. There is no limit to the size of the solar cell. It is preferably 0.5 m 2 to 3 m 2 .
  • composition 1 for forming a passivation layer A stearamide solution was prepared by mixing 5.0 g of stearamide and 45.0 g of terpineol and stirring at 130 ° C. for 1 hour. 10.01 g of ethyl cellulose and 90.02 g of terpineol were mixed and stirred at 150 ° C. for 1 hour to prepare an ethyl cellulose solution.
  • Passivation layer 2.22 g of niobium ethoxide, 2.23 g of (ethylacetoacetate) aluminum isopropoxide, 1.88 g of terpineol, 1.58 g of stearamide solution, and 7.92 g of ethylcellulose solution.
  • a forming composition 1 was prepared. The content of stearamide in the composition 1 for forming a passivation layer was 1.0%, and the content of the compound of formula (I) was 14.0%.
  • the shear viscosity of the composition 1 for forming a passivation layer prepared above was measured immediately after preparation (within 12 hours) and after storage at 25 ° C. for 30 days, respectively.
  • the shear viscosity was measured by mounting a cone plate (diameter 50 nm, cone angle 1 °) on Anton Paar, MCR301, at a temperature of 25 ° C. and a shear rate of 1.0 s ⁇ 1 .
  • the shear viscosity at 25 ° C. was 28.2 Pa ⁇ s immediately after preparation, and 29.8 Pa ⁇ s after storage at 25 ° C. for 30 days.
  • a single crystal p-type silicon substrate (SUMCO, 50 mm square, thickness: 770 ⁇ m) having a mirror-shaped surface was used.
  • the composition 1 for forming a passivation layer obtained above was applied onto a silicon substrate using a screen printing method.
  • the composition 1 for forming a passivation layer was applied in such an amount that the average thickness of the passivation layer obtained after heat treatment (firing) was 300 ⁇ m.
  • the above printing was performed 10 times continuously, and it was visually confirmed that no printing unevenness was found on all 10 sheets.
  • the printing unevenness refers to a portion that is formed thinner than the surroundings because a part of the screen plate is poorly separated when the screen plate is separated from the silicon substrate.
  • the state where the coating film is uniform means that the composition for forming a passivation layer is present on the entire printed portion on the silicon substrate.
  • the silicon substrate provided with the passivation layer forming composition 1 was dried at 150 ° C. for 5 minutes.
  • the substrate was heat-treated (fired) at 700 ° C. for 10 minutes and then allowed to cool at room temperature to produce an evaluation substrate.
  • Heat treatment (firing) is carried out using a diffusion furnace (horizontal diffusion furnace DD-200P, Hitachi Kokusai Electric Inc.) under atmospheric conditions (flow rate: 5 L / min), maximum temperature 700 ° C., holding time 10 minutes. went.
  • the average thickness of the obtained passivation layer was calculated as an arithmetic average value by measuring the thickness at three points by a conventional method using a stylus type step / surface shape measuring device (Ambios).
  • the effective lifetime ( ⁇ s) of the region where the passivation layer of the evaluation substrate obtained above was formed was quasi-stationary at room temperature (25 ° C.) using a lifetime measurement device (Sinton Instruments, WCT-120). Measured by state photoconductivity method. The effective lifetime was 880 ⁇ s.
  • a polyethylene glycol solution was prepared by mixing 5.0 g of polyethylene glycol (number average molecular weight 4000) and 45.0 g of terpineol and stirring at 100 ° C. for 1 hour. Formation of a passivation layer by mixing 2.11 g of niobium ethoxide, 2.17 g of (ethylacetoacetato) aluminum isopropoxide, 1.75 g of terpineol, 1.51 g of polyethylene glycol solution, and 7.55 g of ethyl cellulose solution Composition 2 was prepared. The content of polyethylene glycol in the composition 2 for forming a passivation layer was 1.0%, and the content of the compound of formula (I) was 14.0%. The viscosity of the composition 2 for forming a passivation layer 2 was 35.5 Pa ⁇ s immediately after preparation and 37.8 Pa ⁇ s after storage at 25 ° C. for 30 days.
  • a passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the passivation layer forming composition 2 prepared above was used, and evaluated in the same manner. Of the 10 screen prints, 9 had no printing unevenness. Of the 10 sheets, 7 were uniform. The effective lifetime was 801 ⁇ s.
  • Example 3 2.12 g of niobium ethoxide, 2.18 g of (ethylacetoacetato) aluminum isopropoxide, 1.80 g of terpineol, MR-2G (organic filler, Soken Chemical Co., Ltd., PMMA resin filler, volume average particle diameter 1 1.0 ⁇ m) and 7.61 g of ethyl cellulose solution were mixed to prepare a passivation layer forming composition 3.
  • the content of MR-2G (denoted as MR in the table) in the composition 3 for forming a passivation layer of MR was 9.9%, and the content of the compound of formula (I) was 13.9%.
  • the viscosity of the composition 3 for forming a passivation layer 3 was 28.2 Pa ⁇ s immediately after preparation and 32.3 Pa ⁇ s after storage at 25 ° C. for 30 days.
  • a passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the composition 3 for forming a passivation layer prepared above was used, and evaluated in the same manner. Of the 10 screen prints, 10 had no printing unevenness. Of the 10 sheets, 10 were uniform. The effective lifetime was 627 ⁇ s.
  • Example 1 a substrate for evaluation was prepared, and the effective lifetime was measured and evaluated in the same manner as in Example 1 except that the composition 1 for forming a passivation layer 1 was not applied. The effective lifetime was 20 ⁇ s.
  • composition C1 2.10 g of niobium ethoxide, 2.17 g of (ethylacetoaceto) aluminum isopropoxide, 3.31 g of terpineol, and 7.63 g of ethylcellulose solution were mixed to prepare composition C1.
  • the viscosity of the composition C1 was 23.5 Pa ⁇ s immediately after preparation, and 24.8 Pa ⁇ s after storage at 25 ° C. for 30 days.
  • a passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the composition C1 prepared above was used, and evaluated in the same manner. Of the 10 screen prints, 4 had no printing unevenness. Of the 10 sheets, the number of the coated films was uniform. The effective lifetime was 1077 ⁇ s.
  • composition C2 0.80 g of stearamide solution and 7.81 g of ethylcellulose solution were mixed to prepare composition C2.
  • the viscosity of the composition C2 was 27.2 Pa ⁇ s immediately after preparation and 28.0 Pa ⁇ s after storage at 25 ° C. for 30 days.
  • a passivation layer was formed on a silicon substrate in the same manner as in Example 1 except that the composition C2 prepared above was used, and evaluated in the same manner. Of the 10 screen prints, 9 had no printing unevenness. Of the 10 sheets, 9 were uniform. The effective lifetime was 24 ⁇ s.
  • composition C3 8.13 g of niobium chloride, 2.14 g of (ethylacetoacetate) aluminum isopropoxide, 1.79 g of terpineol, 1.55 g of stearamide solution, and 7.84 g of ethylcellulose solution were mixed to obtain composition C3 Was prepared.
  • the viscosity of the composition C1 was 28.6 Pa ⁇ s immediately after preparation, and 58.4 Pa ⁇ s after storage at 25 ° C. for 30 days.
  • the change rate of shear viscosity after storage for 30 days is less than 10%, A is 10% or more and less than 30%, B is 30% or more, and C is marked. To do. If evaluation is A and B, it is favorable as the storage stability of the composition for forming a passivation layer. Also, in the printability item, 9 or more out of 10 sheets that did not cause printing unevenness during printing were A, 8 or less and 6 or more B, and 5 or less. Indicated as C. In addition, in the item of coating film uniformity, when the coating film was visually uniform after printing, 9 out of 10 sheets were A, 8 sheets or less and 6 sheets or more were B, 5 sheets or less The thing is written as C.
  • the composition for forming a passivation layer of the present invention is excellent in storage stability. Moreover, it turns out that the passivation layer which has the outstanding passivation effect can be formed by using the composition for passivation layer formation of this invention. Moreover, it turns out that a passivation layer can be formed in a desired shape by a simple process by using the composition for forming a passivation layer of the present invention. Further, it can be seen that the passivation layer forming compositions of Examples 1 to 3 are excellent in printability and coating film uniformity.
  • a passivation film used for a solar cell element including aluminum oxide and niobium oxide and having a silicon substrate.
  • niobium oxide / aluminum oxide a mass ratio (niobium oxide / aluminum oxide) between the niobium oxide and the aluminum oxide is 30/70 to 90/10.
  • ⁇ 3> The passivation film according to ⁇ 1> or ⁇ 2>, in which a total content of the niobium oxide and the aluminum oxide is 90% by mass or more.
  • the passivation film according to any one of ⁇ 1> to ⁇ 4> which is a heat-treated product of a coating type material including an aluminum oxide precursor and a niobium oxide precursor.
  • a p-type silicon substrate made of single crystal silicon or polycrystalline silicon and having a light receiving surface and a back surface opposite to the light receiving surface;
  • An n-type impurity diffusion layer formed on the light-receiving surface side of the silicon substrate;
  • a first electrode formed on the surface of the n-type impurity diffusion layer on the light-receiving surface side of the silicon substrate;
  • a passivation film comprising aluminum oxide and niobium oxide formed on the back surface of the silicon substrate and having a plurality of openings;
  • a second electrode forming an electrical connection with the surface on the back side of the silicon substrate through the plurality of openings;
  • a solar cell element comprising:
  • a p-type silicon substrate made of single crystal silicon or polycrystalline silicon and having a light receiving surface and a back surface opposite to the light receiving surface;
  • An n-type impurity diffusion layer formed on the light-receiving surface side of the silicon substrate;
  • a first electrode formed on the surface of the n-type impurity diffusion layer on the light-receiving surface side of the silicon substrate;
  • a p-type impurity diffusion layer formed on a part or all of the back side of the silicon substrate and doped with impurities at a higher concentration than the silicon substrate;
  • a passivation film comprising aluminum oxide and niobium oxide formed on the back surface of the silicon substrate and having a plurality of openings;
  • a second electrode that forms an electrical connection with the surface of the p-type impurity diffusion layer on the back side of the silicon substrate through the plurality of openings;
  • a solar cell element comprising:
  • An n-type silicon substrate made of single crystal silicon or polycrystalline silicon and having a light receiving surface and a back surface opposite to the light receiving surface;
  • a p-type impurity diffusion layer formed on the light-receiving surface side of the silicon substrate;
  • a second electrode formed on the back side of the silicon substrate;
  • a passivation film formed on the light-receiving surface side surface of the silicon substrate and including a plurality of openings and containing aluminum oxide and niobium oxide;
  • a first electrode formed on the surface of the p-type impurity diffusion layer on the light-receiving surface side of the silicon substrate and forming an electrical connection with the surface on the light-receiving surface side of the silicon substrate through the plurality of openings;
  • a solar cell element comprising:
  • ⁇ 10> The solar cell element according to any one of ⁇ 7> to ⁇ 9>, wherein a mass ratio of niobium oxide to aluminum oxide (niobium oxide / aluminum oxide) in the passivation film is 30/70 to 90/10.
  • ⁇ 11> The solar cell element according to any one of ⁇ 7> to ⁇ 10>, wherein a total content of the niobium oxide and the aluminum oxide in the passivation film is 90% by mass or more.
  • ⁇ 12> a silicon substrate;
  • a passivation film having a long carrier lifetime of a silicon substrate and having a negative fixed charge can be realized at low cost.
  • a coating type material for realizing the formation of the passivation film can be provided.
  • a highly efficient solar cell element using the passivation film can be realized at low cost.
  • a silicon substrate with a passivation film having a long carrier lifetime and a negative fixed charge can be realized at low cost.
  • the passivation film of the present embodiment is a passivation film used for a silicon solar cell element, and includes aluminum oxide and niobium oxide.
  • the fixed charge amount of the film can be controlled by changing the composition of the passivation film.
  • the mass ratio of niobium oxide and aluminum oxide is 30/70 to 80/20 from the viewpoint that the negative fixed charge can be stabilized. Further, the mass ratio of niobium oxide and aluminum oxide is more preferably 35/65 to 70/30 from the viewpoint that the negative fixed charge can be further stabilized. Further, the mass ratio of niobium oxide and aluminum oxide is preferably 50/50 to 90/10 from the viewpoint that both improvement of carrier lifetime and negative fixed charge can be achieved.
  • the mass ratio of niobium oxide to aluminum oxide in the passivation film is measured by energy dispersive X-ray spectroscopy (EDX), secondary ion mass spectrometry (SIMS), and high frequency inductively coupled plasma mass spectrometry (ICP-MS). be able to.
  • Specific measurement conditions are as follows. Dissolving the passivation film in acid or alkaline aqueous solution, atomizing this solution and introducing it into Ar plasma, measuring the wavelength and intensity by spectroscopically analyzing the light emitted when the excited element returns to the ground state, Element qualification is performed from the obtained wavelength, and quantification is performed from the obtained intensity.
  • the total content of niobium oxide and aluminum oxide in the passivation film is preferably 80% by mass or more, and more preferably 90% by mass or more from the viewpoint of maintaining good characteristics. As the components of niobium oxide and aluminum oxide in the passivation film increase, the effect of negative fixed charges increases.
  • the total content of niobium oxide and aluminum oxide in the passivation film can be measured by combining thermogravimetric analysis, fluorescent X-ray analysis, ICP-MS, and X-ray absorption spectroscopy. Specific measurement conditions are as follows.
  • the ratio of inorganic components can be calculated by thermogravimetric analysis, the ratio of niobium and aluminum can be calculated by fluorescent X-ray or ICP-MS analysis, and the ratio of oxide can be examined by X-ray absorption spectroscopy.
  • components other than niobium oxide and aluminum oxide may be included as organic components from the viewpoint of improving the film quality and adjusting the elastic modulus.
  • the presence of the organic component in the passivation film can be confirmed by elemental analysis and measurement of the FT-IR of the film.
  • the content of the organic component in the passivation film is more preferably less than 10% by mass, further preferably 5% by mass or less, and particularly preferably 1% by mass or less in the passivation film.
  • the passivation film may be obtained as a heat-treated product of a coating type material containing an aluminum oxide precursor and a niobium oxide precursor. Details of the coating type material will be described next.
  • the coating material of the present embodiment includes an aluminum oxide precursor and a niobium oxide precursor, and is used for forming a passivation film for a solar cell element having a silicon substrate.
  • the aluminum oxide precursor can be used without particular limitation as long as it produces aluminum oxide.
  • As the aluminum oxide precursor it is preferable to use an organic aluminum oxide precursor from the viewpoint of uniformly dispersing aluminum oxide on the silicon substrate and chemically stable.
  • organic aluminum oxide precursors include aluminum triisopropoxide (structural formula: Al (OCH (CH 3 ) 2 ) 3 , High Purity Chemical Research Laboratory SYM-AL04, and the like.
  • the niobium oxide precursor can be used without particular limitation as long as it produces niobium oxide.
  • the niobium oxide precursor it is preferable to use an organic niobium oxide precursor from the viewpoint of uniformly dispersing niobium oxide on the silicon substrate and chemically stable.
  • organic niobium oxide precursors include niobium (V) ethoxide (structural formula: Nb (OC 2 H 5 ) 5 , molecular weight: 318.21), High Purity Chemical Laboratory Nb-05, etc. be able to.
  • a passivation film is formed by forming a coating type material containing an organic niobium oxide precursor and an organic aluminum oxide precursor using a coating method or a printing method, and then removing organic components by a subsequent heat treatment (firing). Can be obtained. Therefore, as a result, a passivation film containing an organic component may be used.
  • FIGS. 5 to FIG. 8 are cross-sectional views showing first to fourth configuration examples of the solar cell element using the passivation film on the back surface of the present embodiment.
  • silicon substrate (crystalline silicon substrate, semiconductor substrate) 101 used in this embodiment mode either single crystal silicon or polycrystalline silicon may be used. Further, as the silicon substrate 101, either p-type crystalline silicon or n-type crystalline silicon may be used. From the standpoint of exerting the effects of the present embodiment, p-type crystalline silicon is more suitable.
  • the single crystal silicon or polycrystalline silicon used for the silicon substrate 101 may be arbitrary, but single crystal silicon or polycrystalline silicon having a resistivity of 0.5 ⁇ ⁇ cm to 10 ⁇ ⁇ cm is preferable.
  • a light receiving surface antireflection film 103 such as a silicon nitride (SiN) film, and a first electrode 105 (light receiving surface side electrode, first surface electrode, upper surface electrode) using silver (Ag) or the like. , A light receiving surface electrode) is formed.
  • the light receiving surface antireflection film 103 may also have a function as a light receiving surface passivation film. By using the SiN film, both functions of the light receiving surface antireflection film and the light receiving surface passivation film can be provided.
  • the solar cell element of the present embodiment may or may not have the light-receiving surface antireflection film 103.
  • the light receiving surface of the solar cell element is preferably formed with a concavo-convex structure (texture structure) in order to reduce the reflectance on the surface, but the solar cell element of the present embodiment has a texture structure. It may or may not have.
  • a BSF (Back Surface Field) layer 104 which is a layer doped with a group III element such as aluminum or boron, is formed on the back side (lower side, second side, back side in the figure) of the silicon substrate 101.
  • the solar cell element of this embodiment may or may not have the BSF layer 104.
  • a second surface made of aluminum or the like is used on the back surface side of the silicon substrate 101 to make contact (electrical connection) with the BSF layer 104 (or the surface on the back surface side of the silicon substrate 101 when the BSF layer 104 is not provided). Electrodes 106 (back side electrode, second side electrode, back side electrode) are formed.
  • a contact region (a surface on the back side of the silicon substrate 101 when the BSF layer 104 is not provided) and the second electrode 106 are electrically connected (
  • a passivation film (passivation layer) 107 containing aluminum oxide and niobium oxide is formed in a portion excluding the opening OA).
  • the passivation film 107 of this embodiment can have a negative fixed charge. With this fixed charge, electrons which are minority carriers among the carriers generated in the silicon substrate 101 by light are bounced back to the surface side. For this reason, a short circuit current increases and it is anticipated that photoelectric conversion efficiency will improve.
  • FIG. 6 a second configuration example shown in FIG. 6 will be described.
  • the second electrode 106 is formed on the entire surface of the contact region (opening OA) and the passivation film 107, but in FIG. 6 (second configuration example) The second electrode 106 is formed only in the region (opening OA). The second electrode 106 may be formed only in part on the contact region (opening OA) and the passivation film 107. Even with the solar cell element having the configuration shown in FIG. 6, the same effect as in FIG. 5 (first configuration example) can be obtained.
  • the BSF layer 104 is formed only on a part of the back surface side including the contact region (opening OA portion) with the second electrode 106, and FIG. 5 (first configuration example). Thus, it is not formed on the entire back surface side. Even with the solar cell element having such a configuration (FIG. 7), the same effect as that of FIG. 5 (first configuration example) can be obtained. Further, according to the solar cell element of the third configuration example of FIG. 7, impurities are doped at a higher concentration than the silicon substrate 101 by doping the BSF layer 104, that is, a group III element such as aluminum or boron. Since the area is small, it is possible to obtain higher photoelectric conversion efficiency than that in FIG. 5 (first configuration example).
  • FIG. 8 a fourth configuration example shown in FIG. 8 will be described.
  • the second electrode 106 is formed on the entire surface of the contact region (opening OA) and the passivation film 107, but in FIG. 8 (fourth configuration example), the contact is formed.
  • the second electrode 106 is formed only in the region (opening OA).
  • the second electrode 106 may be formed only in part on the contact region (opening OA) and the passivation film 107. Even with the solar cell element having the configuration shown in FIG. 8, the same effect as that of FIG. 7 (third configuration example) can be obtained.
  • the second electrode 106 when the second electrode 106 is applied by a printing method and baked at a high temperature to form the entire surface on the back side, a convex warpage tends to occur in the temperature lowering process. Such warpage may cause damage to the solar cell element, which may reduce the yield. Further, the problem of warpage increases as the silicon substrate becomes thinner. The cause of this warp is that stress is generated because the thermal expansion coefficient of the second electrode 106 made of metal (for example, aluminum) is larger than that of the silicon substrate, and the shrinkage in the temperature lowering process is correspondingly large.
  • metal for example, aluminum
  • the electrode structure tends to be symmetrical vertically. This is preferable because stress due to the difference in thermal expansion coefficient is unlikely to occur. However, in that case, it is preferable to provide a separate reflective layer.
  • a texture structure is formed on the surface of the silicon substrate 101 shown in FIG.
  • the texture structure may be formed on both sides of the silicon substrate 101 or only on one side (light receiving side).
  • the damaged layer of the silicon substrate 101 is removed by immersing the silicon substrate 101 in a heated potassium hydroxide or sodium hydroxide solution.
  • a texture structure is formed on both surfaces or one surface (light receiving surface side) of the silicon substrate 101 by dipping in a solution containing potassium hydroxide and isopropyl alcohol as main components. Note that, as described above, the solar cell element of the present embodiment may or may not have a texture structure, and thus this step may be omitted.
  • a phosphorus diffusion layer (n + layer) is formed as the diffusion layer 102 by thermal diffusion of phosphorus oxychloride (POCl 3 ) or the like on the silicon substrate 101.
  • the phosphorus diffusion layer can be formed, for example, by applying a coating-type doping material solution containing phosphorus to the silicon substrate 101 and performing heat treatment. After the heat treatment, the phosphorous glass layer formed on the surface is removed with an acid such as hydrofluoric acid, whereby a phosphorous diffusion layer (n + layer) is formed as the diffusion layer 102.
  • the method for forming the phosphorus diffusion layer is not particularly limited.
  • the phosphorus diffusion layer may be formed so that the depth from the surface of the silicon substrate 101 is in the range of 0.2 ⁇ m to 0.5 ⁇ m, and the sheet resistance is in the range of 40 ⁇ / ⁇ to 100 ⁇ / ⁇ (ohm / square). preferable.
  • a BSF layer 104 on the back surface side is formed by applying a coating-type doping material solution containing boron, aluminum or the like to the back surface side of the silicon substrate 101 and performing heat treatment.
  • a coating-type doping material solution containing boron, aluminum or the like for the application, methods such as screen printing, inkjet, dispensing, spin coating and the like can be used.
  • the BSF layer 104 is formed by removing a layer of boron glass, aluminum, or the like formed on the back surface with hydrofluoric acid, hydrochloric acid, or the like.
  • the method for forming the BSF layer 104 is not particularly limited.
  • the BSF layer 104 is formed so that the concentration range of boron, aluminum, etc.
  • the solar cell element of the present embodiment may or may not have the BSF layer 104, and thus this step may be omitted.
  • the diffusion layer 102 on the light-receiving surface and the BSF layer 104 on the back surface are formed using a coating-type doping material solution
  • the above-described doping material solution is applied to both sides of the silicon substrate 101 to diffuse.
  • the phosphorous diffusion layer (n + layer) and the BSF layer 104 as the layer 102 may be formed in a lump, and then phosphorous glass, boron glass, or the like formed on the surface may be removed all at once.
  • a silicon nitride film as the light-receiving surface antireflection film 103 is formed on the diffusion layer 102.
  • the method for forming the light receiving surface antireflection film 103 is not particularly limited.
  • the light-receiving surface antireflection film 103 is preferably formed to have a thickness in the range of 50 to 100 nm and a refractive index in the range of 1.9 to 2.2.
  • the light-receiving surface antireflection film 103 is not limited to a silicon nitride film, and may be a silicon oxide film, an aluminum oxide film, a titanium oxide film, or the like.
  • the surface antireflection film 103 such as an silicon nitride film can be formed by a method such as plasma CVD or thermal CVD, and is preferably formed by plasma CVD that can be formed in a temperature range of 350 ° C. to 500 ° C.
  • the passivation film 107 contains aluminum oxide and niobium oxide.
  • an aluminum oxide precursor typified by an organometallic decomposition coating material from which aluminum oxide can be obtained by heat treatment (firing), and niobium oxide obtained by heat treatment (firing). It is formed by applying a material (passivation material) containing a niobium oxide precursor typified by a commercially available organometallic decomposition coating type material and heat-treating (firing).
  • the formation of the passivation film 107 can be performed as follows, for example.
  • the above coating material is spin-coated on one side of a 725 ⁇ m thick 8-inch (20.32 cm) p-type silicon substrate (8 ⁇ cm to 12 ⁇ cm) from which a natural oxide film has been previously removed with hydrofluoric acid having a concentration of 0.049% by mass
  • pre-baking is performed on a hot plate at 120 ° C. for 3 minutes. Thereafter, heat treatment is performed at 650 ° C. for 1 hour in a nitrogen atmosphere. In this case, a passivation film containing aluminum oxide and niobium oxide is obtained.
  • the thickness of the passivation film 107 formed by the above method is usually about several tens of nanometers as measured by an ellipsometer.
  • the coating type material is applied to a predetermined pattern including the contact area (opening OA) by a method such as screen printing, offset printing, inkjet printing, or dispenser printing.
  • the above-mentioned coating type material is pre-baked in the range of 80 ° C. to 180 ° C. after evaporation to evaporate the solvent, and then at 600 ° C. to 1000 ° C. for 30 minutes to 3 hours in a nitrogen atmosphere or in air. It is preferable to perform a degree of heat treatment (annealing) to form a passivation film 107 (oxide film).
  • the opening (contact hole) OA is preferably formed in a dot shape or a line shape on the BSF layer 104.
  • the mass ratio of niobium oxide to aluminum oxide is preferably 30/70 to 90/10, and preferably 30/70 to 80/20. More preferably, it is more preferably 35/65 to 70/30. Thereby, the negative fixed charge can be stabilized. Further, the mass ratio of niobium oxide and aluminum oxide is preferably 50/50 to 90/10 from the viewpoint that both improvement of carrier lifetime and negative fixed charge can be achieved.
  • the total content of niobium oxide and aluminum oxide is preferably 80% by mass or more, and more preferably 90% by mass or more.
  • the first electrode 105 which is an electrode on the light receiving surface side is formed.
  • the first electrode 105 is formed by forming a paste mainly composed of silver (Ag) on the light-receiving surface antireflection film 103 by screen printing and performing a heat treatment (fire through).
  • the shape of the 1st electrode 105 may be arbitrary shapes, for example, may be a known shape which consists of a finger electrode and a bus-bar electrode.
  • the second electrode 106 which is an electrode on the back side is formed.
  • the second electrode 106 can be formed by applying a paste containing aluminum as a main component using screen printing or a dispenser and heat-treating it.
  • the shape of the second electrode 106 is preferably the same shape as the shape of the BSF layer 104, a shape covering the entire back surface, a comb shape, a lattice shape, or the like.
  • the paste for forming the first electrode 105 and the second electrode 106, which are the electrodes on the light receiving surface side, is first printed, and then heat-treated (fire-through), whereby the first electrode 105 and the second electrode 106 are formed.
  • the two electrodes 106 may be formed together.
  • the BSF layer 104 is formed in a contact portion between the second electrode 106 and the silicon substrate 101 in a self-alignment manner. Is formed.
  • the BSF layer 104 may be separately formed by applying a coating-type doping material solution containing boron, aluminum, or the like to the back side of the silicon substrate 101 and heat-treating it. .
  • the diffusion layer 102 is formed by a layer doped with a group III element such as boron
  • the BSF layer 104 is formed by doping a group V element such as phosphorus.
  • a leakage current flows through a portion where the inversion layer formed at the interface due to the negative fixed charge and the metal on the back surface are in contact with each other, and the conversion efficiency may be difficult to increase.
  • FIG. 9 is a cross-sectional view illustrating a configuration example of a solar cell element using the light-receiving surface passivation film of the present embodiment.
  • the diffusion layer 102 on the light receiving surface side is p-type doped with boron, and collects holes on the light receiving surface side and electrons on the back surface side of the generated carriers. For this reason, it is preferable that the passivation film 107 having a negative fixed charge is on the light receiving surface side.
  • an antireflection film made of SiN or the like may be further formed by CVD or the like.
  • the passivation material (a-1) is spin-coated on one side of a 725 ⁇ m-thick 8-inch p-type silicon substrate (8 ⁇ cm to 12 ⁇ cm) from which a natural oxide film has been removed in advance with a hydrofluoric acid having a concentration of 0.049% by mass.
  • Pre-baking was performed on the plate at 120 ° C. for 3 minutes.
  • the FT-IR of the passivation film was measured, a very few peaks due to alkyl groups were observed in the vicinity of 1200 cm ⁇ 1 .
  • a plurality of aluminum electrodes having a diameter of 1 mm were formed on the above-described passivation film through a metal mask by vapor deposition, thereby manufacturing a capacitor having a metal-insulator-semiconductor (MIS) structure.
  • the voltage dependence (CV characteristics) of the capacitance of this capacitor was measured with a commercially available prober and LCR meter (HP, 4275A). As a result, it was found that the flat band voltage (Vfb) shifted from an ideal value of ⁇ 0.81V to + 0.32V. From this shift amount, it was found that the passivation film obtained from the passivation material (a-1) showed a negative fixed charge with a fixed charge density (Nf) of ⁇ 7.4 ⁇ 10 11 cm ⁇ 2 .
  • the passivation material (a-1) is applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and subjected to a heat treatment (firing) at 650 ° C. for 1 hour in a nitrogen atmosphere.
  • a sample in which both surfaces of the substrate were covered with a passivation film was produced.
  • the carrier lifetime of this sample was measured using a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540). As a result, the carrier lifetime was 530 ⁇ s.
  • the same 8-inch p-type silicon substrate was measured by passivation using the iodine passivation method, and the carrier lifetime was 1100 ⁇ s.
  • the passivation film obtained by heat-treating (firing) the passivation material (a-1) showed a certain degree of passivation performance and a negative fixed charge.
  • Reference Example 1-2 Similar to Reference Example 1-1, a commercially available organometallic decomposition coating material from which aluminum oxide (Al 2 O 3 ) can be obtained by heat treatment (calcination) [High-Purity Chemical Laboratory, SYM-AL04, concentration 2. 3 mass%] and a commercially available organometallic decomposable coating type material [High Purity Chemical Laboratory, Nb-05, concentration 5 mass%] from which niobium oxide (Nb 2 O 5 ) can be obtained by heat treatment (firing). Passivation materials (a-2) to (a-7) shown in Table 2 were prepared by mixing at different ratios.
  • each of the passivation materials (a-2) to (a-7) was applied to one side of a p-type silicon substrate, and heat treatment (firing) was performed to produce a passivation film.
  • the voltage dependence of the capacitance of the obtained passivation film was measured, and the fixed charge density was calculated therefrom.
  • the carrier lifetime is also increased after heat treatment (firing). Since it showed a certain value, it was suggested that it functions as a passivation film. It was found that all the passivation films obtained from the passivation materials (a-2) to (a-7) stably show negative fixed charges and can be suitably used as a passivation for a p-type silicon substrate. .
  • the passivation material (c-1) is spin-coated on one side of a 725 ⁇ m-thick 8-inch p-type silicon substrate (8 ⁇ cm to 12 ⁇ cm) from which a natural oxide film has been removed in advance with a hydrofluoric acid having a concentration of 0.049% by mass.
  • Pre-baking was performed at 120 ° C. for 3 minutes on the plate.
  • heat treatment was performed at 600 ° C. for 1 hour in a nitrogen atmosphere to obtain a passivation film containing aluminum oxide and niobium oxide. When the film thickness was measured with an ellipsometer, it was 50 nm.
  • a plurality of aluminum electrodes having a diameter of 1 mm were formed on the above-described passivation film through a metal mask by vapor deposition, thereby manufacturing a capacitor having a metal-insulator-semiconductor (MIS) structure.
  • the voltage dependence (CV characteristics) of the capacitance of this capacitor was measured with a commercially available prober and LCR meter (HP, 4275A). As a result, it was found that the flat band voltage (Vfb) shifted from an ideal value of ⁇ 0.81 V to +4.7 V. From this shift amount, it was found that the passivation film obtained from the passivation material (c-1) showed a negative fixed charge with a fixed charge density (Nf) of ⁇ 3.2 ⁇ 10 12 cm ⁇ 2 .
  • the passivation material (c-1) was applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and subjected to heat treatment (baking) at 600 ° C. for 1 hour in a nitrogen atmosphere to obtain silicon.
  • a sample in which both surfaces of the substrate were covered with a passivation film was produced.
  • the carrier lifetime of this sample was measured using a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540). As a result, the carrier lifetime was 330 ⁇ s.
  • the same 8-inch p-type silicon substrate was measured by passivation using the iodine passivation method, and the carrier lifetime was 1100 ⁇ s.
  • the passivation film obtained by heat-treating (sintering) the passivation material (c-1) exhibited a certain degree of passivation performance and a negative fixed charge.
  • the passivation material (c-2) is spin-coated on one side of a 725 ⁇ m-thick 8-inch p-type silicon substrate (8 ⁇ cm to 12 ⁇ cm) from which a natural oxide film has been removed in advance with a hydrofluoric acid having a concentration of 0.049% by mass.
  • Pre-baking was performed at 120 ° C. for 3 minutes on the plate.
  • heat treatment was performed at 600 ° C. for 1 hour in a nitrogen atmosphere to obtain a passivation film containing aluminum oxide and niobium oxide. When the film thickness was measured by an ellipsometer, it was 14 nm.
  • a plurality of 1 mm diameter aluminum electrodes are deposited on the passivation film through a metal mask to form a MIS (Metal-Insulator-Semiconductor) capacitor.
  • the voltage dependence (CV characteristics) of the capacitance of this capacitor was measured with a commercially available prober and LCR meter (HP, 4275A).
  • Vfb flat band voltage
  • LCR meter HP, 4275A
  • Vfb flat band voltage
  • the passivation film obtained from the passivation material (c-2) showed a negative fixed charge with a fixed charge density (Nf) of ⁇ 0.8 ⁇ 10 11 cm ⁇ 2 .
  • the passivation material (c-2) is applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and subjected to heat treatment (firing) at 600 ° C. for 1 hour in a nitrogen atmosphere.
  • a sample in which both surfaces of the substrate were covered with a passivation film was produced.
  • the carrier lifetime of this sample was measured with a lifetime measuring device (Kobelco Research Institute Co., Ltd., RTA-540). As a result, the carrier lifetime was 200 ⁇ s.
  • the same 8-inch p-type silicon substrate was measured by passivation using the iodine passivation method, and the carrier lifetime was 1100 ⁇ s.
  • each of the passivation materials (b-1) to (b-7) was applied to one side of a p-type silicon substrate and heat-treated (fired) to produce a passivation film, Using this, the voltage dependence of the capacitance was measured, and the fixed charge density was calculated therefrom.
  • the passivation film obtained from the passivation materials (b-1) to (b-6) has a large carrier lifetime and has a function as a passivation.
  • the niobium oxide / aluminum oxide ratios were 10/90 and 20/80, the fixed charge density values varied greatly, and a negative fixed charge density could not be stably obtained. It was confirmed that a negative fixed charge density can be realized by using niobium oxide.
  • a negative fixed charge is stably generated because a passivation film showing a positive fixed charge is obtained in some cases. It turns out that it has not reached to show.
  • a passivation film exhibiting a fixed charge can be used as a passivation for an n-type silicon substrate.
  • a negative fixed charge density could not be obtained with the passivation material (b-7) containing 100% by mass of aluminum oxide.
  • a passivation material (d-3) As a passivation material (d-3), a commercially available organometallic decomposition coating material [having high purity chemical laboratory Hf-05, concentration 5 mass%] from which hafnium oxide (HfO 2 ) can be obtained by heat treatment (firing) is used. Got ready.
  • each of the passivation materials (d-1) to (d-3) is applied to one side of a p-type silicon substrate, and then heat-treated (fired) to produce a passivation film. Using this, the voltage dependence of the capacitance was measured, and the fixed charge density was calculated therefrom.
  • the passivation films obtained from the passivation materials (d-1) to (d-3) have a small carrier lifetime and an insufficient function as a passivation. It also showed a positive fixed charge.
  • the passivation film obtained from the passivation material (d-3) had a negative fixed charge, but its value was small. It was also found that the carrier lifetime was relatively small and the function as a passivation was insufficient.
  • an SiN film produced by plasma CVD was formed as the light-receiving surface antireflection film 103 on the light-receiving surface side.
  • the passivation material (a-1) prepared in Reference Example 1-1 was applied to the region excluding the contact region (opening OA) on the back surface side of the silicon substrate 101 by the inkjet method. Thereafter, heat treatment was performed to form a passivation film 107 having an opening OA.
  • a sample using the passivation material (c-1) prepared in Reference Example 1-3 was separately prepared as the passivation film 107.
  • a paste mainly composed of silver was screen-printed in the shape of predetermined finger electrodes and bus bar electrodes.
  • a paste mainly composed of aluminum was screen-printed on the entire surface.
  • heat treatment fire-through
  • electrodes first electrode 105 and second electrode 106
  • aluminum is diffused into the opening OA on the back surface to form the BSF layer 104.
  • the fire-through process in which the SiN film is not perforated is described, but the opening OA is first formed in the SiN film by etching or the like, and then the silver electrode is formed. You can also.
  • the passivation film 107 is not formed in the above manufacturing process, aluminum paste is printed on the entire back surface, and the p + layer 114 corresponding to the BSF layer 104 and the electrode 116 corresponding to the second electrode.
  • the characteristic evaluation was performed on the entire surface to form a solar cell element having the structure shown in FIG.
  • characteristic evaluation was performed according to JIS-C-8913 (fiscal 2005) and JIS-C-8914 (fiscal 2005). The results are shown in Table 5.
  • the solar cell element having the passivation film 107 including the niobium oxide and aluminum oxide layers has both increased short-circuit current and open-circuit voltage as compared with the solar cell element not having the passivation film 107, and the conversion efficiency ( It was found that the photoelectric conversion efficiency was improved by 1% at the maximum.
  • a passivation film for use in a solar cell element having a silicon substrate comprising aluminum oxide and an oxide of at least one vanadium group element selected from the group consisting of vanadium oxide and tantalum oxide.
  • ⁇ 2> The passivation film according to ⁇ 1>, wherein a mass ratio of the oxide of the vanadium group element to the aluminum oxide (vanadium group element oxide / aluminum oxide) is 30/70 to 90/10.
  • ⁇ 3> The passivation film according to ⁇ 1> or ⁇ 2>, in which a total content of the oxide of the vanadium group element and the aluminum oxide is 90% or more.
  • the oxide of the vanadium group element includes any of oxides of two or three kinds of vanadium group elements selected from the group consisting of vanadium oxide, niobium oxide, and tantalum oxide. Any one of ⁇ 1> to ⁇ 3> The passivation film according to claim 1.
  • ⁇ 5> Heat treatment of a coating-type material comprising: a precursor of aluminum oxide; and a precursor of an oxide of at least one vanadium group element selected from the group consisting of a precursor of vanadium oxide and a precursor of tantalum oxide.
  • the said passivation film is a solar cell element containing aluminum oxide and the oxide of the at least 1 sort (s) of vanadium group element selected from the group which consists of vanadium oxide and a tantalum oxide.
  • a p-type impurity diffusion layer formed on part or all of the second surface side of the silicon substrate and doped with an impurity at a higher concentration than the silicon substrate,
  • the said passivation film is a solar cell element containing aluminum oxide and the oxide of the at least 1 sort (s) of vanadium group element selected from the group which consists of vanadium oxide and a tantalum oxide.
  • n-type impurity diffusion layer formed on a part or all of the second surface side of the silicon substrate and doped with impurities at a higher concentration than the silicon substrate, The solar cell element according to ⁇ 9>, wherein the second electrode is electrically connected to the n-type impurity diffusion layer through an opening of the passivation film.
  • ⁇ 11> The solar cell element according to any one of ⁇ 7> to ⁇ 10>, wherein a mass ratio of the oxide of the vanadium group element and the aluminum oxide in the passivation film is 30/70 to 90/10 .
  • ⁇ 12> The solar cell element according to any one of ⁇ 7> to ⁇ 11>, wherein the total content of the oxide of the vanadium group element and the aluminum oxide in the passivation film is 90% or more.
  • the oxide of the vanadium group element includes an oxide of two or three vanadium group elements selected from the group consisting of vanadium oxide, niobium oxide, and tantalum oxide, ⁇ 7> to ⁇ 12>
  • the solar cell element according to any one of the above.
  • ⁇ 14> a silicon substrate;
  • a passivation film having a long carrier lifetime of a silicon substrate and having a negative fixed charge can be realized at low cost.
  • a coating type material for realizing the formation of the passivation film can be provided.
  • a low-cost and highly efficient solar cell element using the passivation film can be realized.
  • a silicon substrate with a passivation film having a long carrier lifetime and a negative fixed charge can be realized at low cost.
  • the passivation film of the present embodiment is a passivation film used for a silicon solar cell element, and includes aluminum oxide and an oxide of at least one vanadium group element selected from the group consisting of vanadium oxide and tantalum oxide. It is what was included.
  • the amount of fixed charges possessed by the passivation film can be controlled by changing the composition of the passivation film.
  • the vanadium group element is a Group 5 element in the periodic table, and is an element selected from vanadium, niobium, and tantalum.
  • the mass ratio of the oxide of vanadium group element to aluminum oxide is preferably 35/65 to 90/10, from the viewpoint that the negative fixed charge can be stabilized, and is preferably 50/50 to 90/10. More preferably.
  • the mass ratio of vanadium group element oxide and aluminum oxide in the passivation film is determined by energy dispersive X-ray spectroscopy (EDX), secondary ion mass spectrometry (SIMS), and high frequency inductively coupled plasma mass spectrometry (ICP-MS). ) Can be measured. Specific measurement conditions are as follows in the case of ICP-MS, for example. Dissolving the passivation film in acid or alkaline aqueous solution, atomizing this solution and introducing it into Ar plasma, measuring the wavelength and intensity by spectroscopically analyzing the light emitted when the excited element returns to the ground state, Element qualification is performed from the obtained wavelength, and quantification is performed from the obtained intensity.
  • EDX energy dispersive X-ray spectroscopy
  • SIMS secondary ion mass spectrometry
  • ICP-MS high frequency inductively coupled plasma mass spectrometry
  • the total content of the vanadium group element oxide and aluminum oxide in the passivation film is preferably 80% by mass or more, and more preferably 90% by mass or more from the viewpoint of maintaining good characteristics.
  • the components other than the oxide of vanadium group elements and aluminum oxide in the passivation film increase, the effect of negative fixed charges increases.
  • components other than vanadium group oxide and aluminum oxide may be contained as organic components from the viewpoint of improving the film quality and adjusting the elastic modulus.
  • the presence of the organic component in the passivation film can be confirmed by elemental analysis and measurement of the FT-IR of the film.
  • vanadium oxide As the oxide of the vanadium group element, it is preferable to select vanadium oxide (V 2 O 5 ) from the viewpoint of obtaining a larger negative fixed charge.
  • the passivation film may include two or three vanadium group oxides selected from the group consisting of vanadium oxide, niobium oxide, and tantalum oxide as the vanadium group element oxide.
  • the passivation film is preferably obtained by heat-treating a coating-type material, and can be obtained by forming a coating-type material using a coating method or a printing method, and then removing organic components by heat treatment. More preferred. That is, the passivation film may be obtained as a heat-treated product of a coating type material containing an aluminum oxide precursor and a vanadium group element oxide precursor. Details of the coating type material will be described later.
  • the coating type material of the present embodiment is a coating type material used for a passivation film for a solar cell element having a silicon substrate, and includes a precursor of aluminum oxide, a precursor of vanadium oxide, and a precursor of tantalum oxide. And a precursor of an oxide of at least one vanadium group element selected from the group.
  • a precursor of the oxide of the vanadium group element contained in the coating material a precursor of vanadium oxide (V 2 O 5 ) is selected from the viewpoint of the negative fixed charge of the passivation film formed from the coating material. It is preferable.
  • the coating type material is composed of two or three vanadium group elements selected from the group consisting of vanadium oxide precursors, niobium oxide precursors and tantalum oxide precursors as vanadium group oxide precursors. An oxide precursor may also be included.
  • the aluminum oxide precursor can be used without particular limitation as long as it produces aluminum oxide.
  • As the aluminum oxide precursor it is preferable to use an organic aluminum oxide precursor from the viewpoint of uniformly dispersing aluminum oxide on the silicon substrate and a chemically stable viewpoint.
  • Examples of the organic aluminum oxide precursor include aluminum triisopropoxide (structural formula: Al (OCH (CH 3 ) 2 ) 3 , Kojundo Chemical Laboratory Co., Ltd., SYM-AL04.
  • the precursor of the oxide of the vanadium group element can be used without particular limitation as long as it generates an oxide of the vanadium group element.
  • the vanadium group element oxide precursor is preferably an organic vanadium group oxide oxide precursor from the viewpoint of uniformly dispersing aluminum oxide on the silicon substrate and chemically stable. .
  • organic vanadium oxide precursors examples include vanadium (V) oxytriethoxide (structural formula: VO (OC 2 H 5 ) 3 , molecular weight: 202.13), High Purity Chemical Laboratory, V-02 can be mentioned.
  • organic tantalum oxide precursors include tantalum (V) methoxide (structural formula: Ta (OCH 3 ) 5 , molecular weight: 336.12), Kojundo Chemical Laboratory, Ta-10-P Can be mentioned.
  • organic niobium oxide precursors examples include niobium (V) ethoxide (structural formula: Nb (OC 2 H 5 ) 5 , molecular weight: 318.21), High Purity Chemical Laboratory, Nb-05. Can be mentioned.
  • a passivation film By forming a coating type material containing an organic vanadium group oxide precursor and an organic aluminum oxide precursor using a coating method or a printing method, and then removing the organic components by a heat treatment, A passivation film can be obtained. Therefore, as a result, a passivation film containing an organic component may be used.
  • the content of the organic component in the passivation film is more preferably less than 10% by mass, still more preferably 5% by mass or less, and particularly preferably 1% by mass or less.
  • the solar cell element (photoelectric conversion device) of the present embodiment includes the passivation film (insulating film, protective insulating film) described in the above embodiment in the vicinity of the photoelectric conversion interface of the silicon substrate, that is, aluminum oxide and vanadium oxide. And at least one oxide of a vanadium group element selected from the group consisting of tantalum oxide. By containing aluminum oxide and an oxide of at least one vanadium group element selected from the group consisting of vanadium oxide and tantalum oxide, the carrier lifetime of the silicon substrate can be extended and negative fixed charges can be obtained. And the characteristics (photoelectric conversion efficiency) of the solar cell element can be improved.
  • Passivation of passivation material (a2-1) on one side of a 725 ⁇ m thick 8-inch p-type silicon substrate (8 ⁇ ⁇ cm to 12 ⁇ ⁇ cm) with natural oxide film removed beforehand with hydrofluoric acid at a concentration of 0.49% by mass It was applied and placed on a hot plate and prebaked at 120 ° C. for 3 minutes. Thereafter, a heat treatment (firing) was performed at 700 ° C. for 30 minutes in a nitrogen atmosphere to obtain a passivation film containing vanadium oxide and vanadium oxide [vanadium oxide / aluminum oxide 63/37 (mass%)]. It was 51 nm when the film thickness was measured with the ellipsometer. When the FT-IR of the passivation film was measured, a very few peaks due to alkyl groups were observed in the vicinity of 1200 cm ⁇ 1 .
  • the passivation material (a2-1) was applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and subjected to heat treatment (baking) at 650 ° C. for 1 hour in a nitrogen atmosphere.
  • a sample in which both surfaces of the substrate were covered with a passivation film was produced.
  • the carrier lifetime of this sample was measured with a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540). As a result, the carrier lifetime was 400 ⁇ s.
  • the same 8-inch p-type silicon substrate was measured by passivation using the iodine passivation method, and the carrier lifetime was 1100 ⁇ s.
  • the carrier lifetime was 380 ⁇ s.
  • the decrease in carrier lifetime (from 400 ⁇ s to 380 ⁇ s) was within ⁇ 10%, and the decrease in carrier lifetime was small.
  • the passivation film obtained by heat-treating (sintering) the passivation material (a2-1) showed a certain degree of passivation performance and a negative fixed charge.
  • Reference Example 2-2 Similar to Reference Example 2-1, a commercially available organometallic thin film coated material from which aluminum oxide (Al 2 O 3 ) can be obtained by heat treatment (calcination) [High Purity Chemical Laboratory, SYM-AL04, concentration 2 3 mass%] and a commercially available organometallic thin film coating type material [Vitamin Purity Laboratory, V-02, concentration 2 mass%] from which vanadium oxide (V 2 O 5 ) can be obtained by heat treatment, Passivation materials (a2-2) to (a2-7) shown in Table 6 were prepared by mixing at different ratios.
  • each of the passivation materials (a2-2) to (a2-7) was applied to one side of a p-type silicon substrate and heat-treated (fired) to produce a passivation film.
  • the voltage dependence of the capacitance of the obtained passivation film was measured, and the fixed charge density was calculated therefrom.
  • the carrier lifetime was measured using a sample obtained by applying a passivation material to both sides of a p-type silicon substrate and performing heat treatment (firing).
  • the passivation materials (a2-2) to (a2-7) are all negative after the heat treatment (firing). Since it showed a fixed charge and a certain carrier lifetime, it was suggested that it functions as a passivation film. It was found that all the passivation films obtained from the passivation materials (a2-2) to (a2-7) stably show negative fixed charges and can be suitably used as a passivation for a p-type silicon substrate. .
  • the passivation material (b2-1) was applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and subjected to heat treatment (baking) at 600 ° C. for 1 hour in a nitrogen atmosphere.
  • a sample in which both surfaces of the substrate were covered with a passivation film was produced.
  • the carrier lifetime of this sample was measured by a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540). As a result, the carrier lifetime was 400 ⁇ s.
  • the same 8-inch p-type silicon substrate was measured by passivation using the iodine passivation method, and the carrier lifetime was 1100 ⁇ s.
  • the passivation film obtained by heat-treating (firing) the passivation material (b2-1) exhibits a certain degree of passivation performance and a negative fixed charge.
  • the passivation material (b2-2) was applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and subjected to heat treatment (baking) at 600 ° C. for 1 hour in a nitrogen atmosphere. A sample in which both surfaces of the substrate were covered with a passivation film was produced. The carrier lifetime of this sample was measured by a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540). As a result, the carrier lifetime was 170 ⁇ s. For comparison, the same 8-inch p-type silicon substrate was measured by passivation using the iodine passivation method, and the carrier lifetime was 1100 ⁇ s.
  • the passivation film obtained by curing the passivation material (b2-2) exhibited a certain degree of passivation performance and a negative fixed charge.
  • Each of the passivation materials (c2-1) to (c2-6) is a 725 ⁇ m-thick 8-inch p-type silicon substrate (8 ⁇ ⁇ cm to 12 ⁇ ) from which a natural oxide film has been removed in advance with hydrofluoric acid having a concentration of 0.49% by mass.
  • (Cm) was spin-coated on one side, placed on a hot plate, and pre-baked at 120 ° C. for 3 minutes. Thereafter, a heat treatment (firing) was performed at 700 ° C. for 30 minutes in a nitrogen atmosphere to obtain a passivation film containing aluminum oxide and tantalum oxide. Using this passivation film, the voltage dependence of the capacitance was measured, and the fixed charge density was calculated therefrom.
  • each of the passivation materials (c2-1) to (c2-6) is applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and heat-treated (fired) at 650 ° C. for 1 hour in a nitrogen atmosphere. )
  • the carrier lifetime of this sample was measured by a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540).
  • the passivation materials (c2-1) to (c2-6) are all negative after heat treatment (firing). Since it showed a fixed charge and a certain carrier lifetime, it was suggested that it functions as a passivation film.
  • Al oxide (Al 2 O 3 ) As a compound from which aluminum oxide (Al 2 O 3 ) can be obtained by heat treatment (firing), commercially available aluminum triisopropoxide (structural formula: Al (OCH (CH 3 ) 2 ) 3 , molecular weight: 204.25 2.04 g (0.010 mol) was dissolved in cyclohexane 60 g to prepare a passivation material (d2-1) having a concentration of 5% by mass.
  • Al (OCH (CH 3 ) 2 ) 3 As a compound from which aluminum oxide (Al 2 O 3 ) can be obtained by heat treatment (firing), commercially available aluminum triisopropoxide (structural formula: Al (OCH (CH 3 ) 2 ) 3 , molecular weight: 204.25 2.04 g (0.010 mol) was dissolved in cyclohexane 60 g to prepare a passivation material (d2-1) having a concentration of 5% by mass.
  • the passivation material (d2-1) was applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and subjected to a heat treatment (firing) at 600 ° C. for 1 hour in a nitrogen atmosphere.
  • a sample in which both surfaces of the substrate were covered with a passivation film was produced.
  • the carrier lifetime of this sample was measured by a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540). As a result, the carrier lifetime was 610 ⁇ s.
  • the same 8-inch p-type silicon substrate was measured by passivation using the iodine passivation method, and the carrier lifetime was 1100 ⁇ s.
  • the passivation film obtained by heat-treating the passivation material (d2-1) exhibited a certain degree of passivation performance and a negative fixed charge.
  • the passivation material (d2-2) was applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and subjected to heat treatment (baking) at 600 ° C. for 1 hour in a nitrogen atmosphere. A sample in which both surfaces of the substrate were covered with a passivation film was produced. The carrier lifetime of this sample was measured by a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540). As a result, the carrier lifetime was 250 ⁇ s. For comparison, the same 8-inch p-type silicon substrate was measured by passivation using the iodine passivation method, and the carrier lifetime was 1100 ⁇ s.
  • the passivation film obtained by heat treatment (firing) the passivation material (d2-2) exhibits a certain degree of passivation performance and a negative fixed charge.
  • organometallic thin film coating type material High purity chemical research laboratory SYM-AL04, concentration 2.3 mass%
  • aluminum oxide (Al 2 O 3 ) can be obtained by heat treatment (firing)
  • heat treatment (firing) Niobium oxide (Nb 2 O) by commercially available organometallic thin film coating type material (VCO, Ltd., high purity chemical research laboratory V-02, concentration 2 mass%) from which vanadium oxide (V 2 O 5 ) is obtained, and heat treatment (firing) 5 )
  • a commercially available organometallic thin film coating type material [Co-development High Purity Chemical Laboratory, Nb-05, concentration 5 mass%] obtained is mixed to obtain a passivation material (e2-2) which is a coating type material. Prepared (see Table 8).
  • organometallic thin film coating type material High purity chemical research laboratory SYM-AL04, concentration 2.3 mass%] from which aluminum oxide (Al 2 O 3 ) can be obtained by heat treatment (firing), heat treatment (firing) Niobium oxide (Nb) by commercially available organometallic thin film coating material [Tapurio Chemical Lab. Ta-10-P, concentration 10% by mass] from which tantalum oxide (Ta 2 O 5 ) can be obtained, and heat treatment (firing) 2 O 5 ), a commercially available organometallic thin film coating material [High Purity Chemical Laboratory Nb-05, concentration 5 mass%] is mixed to form a passivation material (e2-3) which is a coating material Was prepared (see Table 8).
  • organometallic thin film coating type material High purity chemical research laboratory SYM-AL04, concentration 2.3 mass%
  • aluminum oxide Al 2 O 3
  • heat treatment firing
  • Tantalum oxide Ti 2 O 5
  • heat treatment Niobium oxide
  • Nb 2 O 5 Niobium oxide
  • a commercially available organometallic thin film coating type material [High purity chemical research laboratory Nb-05, concentration 5 mass%] was mixed to prepare a passivation material (e2-4) as a coating type material (see Table 8).
  • Each of the passivation materials (e2-1) to (e2-4) was 725 ⁇ m thick and 8 inches thick with the natural oxide film removed beforehand with hydrofluoric acid having a concentration of 0.49% by mass, as in Reference Example 2-1. It was spin-coated on one side of a p-type silicon substrate (8 ⁇ ⁇ cm to 12 ⁇ ⁇ cm), placed on a hot plate and prebaked at 120 ° C. for 3 minutes. Thereafter, a heat treatment (firing) was performed at 650 ° C. for 1 hour in a nitrogen atmosphere to obtain a passivation film containing aluminum oxide and two or more vanadium group element oxides.
  • each of the passivation materials (e2-1) to (e2-4) is applied to both sides of an 8-inch p-type silicon substrate, pre-baked, and heat-treated (fired) at 650 ° C. for 1 hour in a nitrogen atmosphere. )
  • the carrier lifetime of this sample was measured by a lifetime measuring device (Kobelco Research Institute, Inc., RTA-540).
  • each of the passivation materials (f2-1) to (f2-9) was applied to one side of a p-type silicon substrate, and then heat treatment (firing) was performed to form a passivation film. This was used to measure the voltage dependence of the capacitance, and the fixed charge density was calculated therefrom.
  • a SiN film was formed on the light receiving surface side by plasma CVD as the light receiving surface antireflection film 103.
  • the passivation material (a2-1) prepared in Reference Example 2-1 was applied to the region excluding the contact region (opening OA) on the back surface side of the silicon substrate 101 by an inkjet method. Thereafter, heat treatment was performed to form a passivation film 107 having an opening OA.
  • a sample using the passivation material (c2-1) prepared in Reference Example 2-5 was separately prepared as the passivation film 107.
  • a paste mainly composed of silver was screen-printed in the shape of predetermined finger electrodes and bus bar electrodes.
  • a paste mainly composed of aluminum was screen-printed on the entire surface.
  • heat treatment fire-through
  • electrodes first electrode 105 and second electrode 106
  • aluminum is diffused into the opening OA on the back surface to form the BSF layer 104.
  • the fire-through process in which the SiN film is not perforated is described.
  • the opening OA is first formed in the SiN film by etching or the like, and then the silver electrode is formed. You can also
  • the passivation film 107 is not formed in the above manufacturing process, aluminum paste is printed on the entire back surface, and the p + layer 114 corresponding to the BSF layer 104 and the electrode 116 corresponding to the second electrode. was formed on the entire surface to form a solar cell element having the structure of FIG.
  • characteristic evaluation a short circuit current, an open circuit voltage, a fill factor, and conversion efficiency
  • the characteristic evaluation was performed according to JIS-C-8913 (fiscal 2005) and JIS-C-8914 (fiscal 2005). The results are shown in Table 10.
  • the solar cell element having the passivation film 107 has both the short-circuit current and the open-circuit voltage increased as compared with the solar electronic element not having the passivation film 107, and the conversion efficiency (photoelectric conversion efficiency) is 0 at the maximum. It was found to improve by 6%.

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JP2021168322A (ja) * 2020-04-09 2021-10-21 国立研究開発法人産業技術総合研究所 太陽電池およびその製造方法

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