TW201605871A - Composition for forming passivation layer, semiconductor substrate with passivation layer, method for producing the same, solar cell element, method for producing the same, and solar cell - Google Patents

Abstract

A composition for forming a first passivation layer containing a compound represented by the following formula (I), water, and a second passivation layer-forming composition comprising a hydrolyzate of a compound represented by the following formula (I). General formula (I): M (OR1 )m In the general formula (I), M represents at least one selected from the group consisting of Al, Nb, Ta, VO, Y, and Hf. R1 The alkyl group or the aryl group is independently represented. m represents an integer from 1 to 5]

Description

Composition for forming passivation layer, semiconductor substrate with passivation layer, method for producing the same, solar cell element, method for producing the same, and solar cell

The present invention relates to a composition for forming a passivation layer, a semiconductor substrate with a passivation layer, a method for producing the same, a solar cell element, a method for producing the same, and a solar cell.

The manufacturing steps of the conventional tantalum solar cell element will be described. First, in order to promote the light confinement effect and achieve high efficiency, a p-type germanium substrate having a textured structure is prepared. Then, the treatment is carried out for several tens of minutes in a mixed gas atmosphere of phosphorus chlorochloride (POCl ₃ ), nitrogen and oxygen at 800 to 900 ° C to form an n-type diffusion layer uniformly on the p-type germanium substrate. In the conventional method, since phosphorus is diffused by using a mixed gas, an n-type diffusion layer is formed not only on the surface of the p-type germanium substrate but also on the side surface and the back surface. Therefore, side etching for removing the n-type diffusion layer formed on the side surface of the p-type germanium substrate is performed. Further, it is necessary to convert the n-type diffusion layer formed on the back surface of the p-type germanium substrate into a p ⁺ -type diffusion layer. Therefore, an aluminum paste containing aluminum powder and a binder is entirely applied to the back surface of the p-type germanium substrate, and heat-treated (calcined), whereby the n-type diffusion layer is converted into a p ⁺ -type diffusion layer, and formed by The aluminum electrode is used to obtain an ohmic contact.

However, the aluminum electrode formed of the aluminum paste has a low electrical conductivity. In order to lower the sheet resistance, in general, the aluminum electrode formed on the entire back surface of the p-type germanium substrate needs to have a thickness of about 10 μm to 20 μm after heat treatment (calcination). In addition, since the thermal expansion coefficient is greatly different between tantalum and aluminum, in the tantalum substrate on which the aluminum electrode is formed, a large internal stress is generated in the tantalum substrate during the heat treatment (calcination) and cooling, and becomes a crystal. Damage to the boundary, growth of crystal defects, and causes of warpage.

In order to solve this problem, there is a method of reducing the amount of coating of the aluminum paste and making the thickness of the back electrode layer thin. However, when the coating amount of the aluminum paste is reduced, the amount of aluminum diffused from the surface of the p-type germanium semiconductor substrate to the inside becomes insufficient. As a result, a desired back surface field (BSF) effect (an effect of improving the collection efficiency of the generated carriers due to the presence of the p ⁺ -type diffusion layer) cannot be achieved, and thus the problem of deterioration in characteristics of the solar cell occurs.

In the above-mentioned Japanese Patent No. 3107287, a point contact method is proposed in which an aluminum paste is applied to a part of the surface of the ruthenium substrate to partially form a p ⁺ -type diffusion layer and an aluminum electrode. In the case of a solar cell having a point contact structure on the opposite surface (hereinafter referred to as "back surface") of such a light receiving surface, it is necessary to suppress the recombination speed of a minority carrier in the surface of a portion other than the aluminum electrode. As a passivation layer for the back surface for solving this problem, an SiO ₂ film or the like is proposed in Japanese Patent Laid-Open Publication No. 2004-6565. The passivation effect by the formation of such an SiO ₂ film has an effect of terminating dangling bonds of germanium atoms in the surface layer portion of the back surface of the tantalum substrate, and reducing the surface level density which causes recombination.

Moreover, as another method of suppressing recombination of minority carriers, there is a method of reducing the minority carrier density by an electric field generated by a fixed charge in the passivation layer. Such a passivation effect is generally called an electric field effect, and as a material having a negative fixed charge, an alumina (Al ₂ O ₃ ) film or the like is proposed in Japanese Patent No. 4767110. Such a passivation layer is generally described by the Journal of Applied Physics, 104 (2008), 113703-1 to 113703-7, generally by atomic layer deposition (ALD), chemical vapor phase. It is formed by a method such as deposition (Chemical Vapor Deposition, CVD). Moreover, as a simple method of forming an aluminum oxide film on a semiconductor substrate, Thin Solid Films, 517 (2009), 6327-6330 and Chinese Physics Letters, 26 (2009), 088102 A method using a sol-gel method is proposed in -1 to 088102-4.

[Problems to be solved by the invention]

The technique described in Journal of Applied Physics, 104 (2008), 113703-1 to 113703-7 includes complicated manufacturing steps such as vapor deposition, and thus it is difficult to improve productivity. Moreover, used in the methods described in Thin Solid Films, 517 (2009), 6327-6330, and Chinese Physics Letters, 26 (2009), 088102-1 to 088102-4. In the composition for forming a passivation layer, since the spin coating method is included in the production step, there is a case where it is difficult to form a film into a target pattern by a short step.

In view of the above-mentioned conventional problems, an object of the present invention is to provide a passivation layer-forming composition which can form a passivation layer which is excellent in pattern formation property and excellent in passivation effect by a simple method. Further, an object of the present invention is to provide a semiconductor substrate with a passivation layer having a passivation layer having an excellent passivation effect obtained by using a composition for forming a passivation layer, a method for producing the same, and an excellent conversion efficiency. Solar cell component and its manufacturing method and solar cell. [Means for solving the problem]

The specific means for achieving the above problems are as follows. <1> A composition for forming a passivation layer, comprising a compound represented by the following formula (I), water; M(OR ¹ ) _m (I) [In the formula (I), M represents a group selected from Al, At least one of the group consisting of Nb, Ta, VO, Y, and Hf; R ¹ each independently represents an alkyl group or an aryl group; m represents an integer of 1 to 5].

<2> A composition for forming a passivation layer, which comprises a hydrolyzate of a compound represented by the following formula (I); M(OR ¹ ) _m (I) [In the formula (I), M represents a group selected from Al At least one of the group consisting of Nb, Ta, VO, Y, and Hf; R ¹ each independently represents an alkyl group or an aryl group; m represents an integer of 1 to 5]. <3> The composition for forming a passivation layer according to <1> or <2>, further comprising a compound represented by the following formula (II);

[Chemical 1]

[In the formula (II), R ² each independently represents an alkyl group; n represents an integer of 1 to 3; and X ² and X ³ each independently represent an oxygen atom or a methylene group; and R ³ , R ⁴ and R ⁵ respectively Independently represents a hydrogen atom or an alkyl group].

The composition for forming a passivation layer according to any one of the above-mentioned items (1), wherein M in the compound represented by the formula (I) is Nb.

The composition for forming a passivation layer according to any one of the above aspects, wherein the mass M1 when heated at 150 ° C for 3 hours is divided by the mass without heating The ratio (M1/M2) calculated by M2 is 0.0001 to 0.7.

The composition for forming a passivation layer according to any one of <1> to <4> wherein a shearing viscosity η1 at a shear rate of 25 ° C of 0.1 s ^-1 is divided by a shear rate of 10.0. The thixotropic ratio (η1/η2) calculated by the shear viscosity η2 of s ^-1 is 1.05 to 100.

The composition for forming a passivation layer according to any one of <1> to <4> wherein the mass M1 when heated at 150 ° C for 3 hours is divided by the mass without heating The ratio (M1/M2) calculated by M2 is 0.0001 to 0.7, and the shear viscosity η1 at a shear rate of 25 ° C of 0.1 s ^-1 is divided by the shear viscosity η 2 of a shear rate of 10.0 s ^-1 . The transformation ratio (η1/η2) is 1.05 to 100.

<8> A semiconductor substrate with a passivation layer, comprising: a semiconductor substrate; and a passivation layer provided in any one of <1> to <7> provided on at least a part of at least one surface of the semiconductor substrate The heat-treated product of the composition for forming a passivation layer.

<9> A method of producing a semiconductor substrate with a passivation layer, comprising: a composition for forming a passivation layer according to any one of <1> to <7>, wherein at least one of the surfaces of at least one of the semiconductor substrates is provided And forming a composition layer; and heat-treating the composition layer to form a passivation layer.

<10> A solar cell element comprising: a semiconductor substrate including a pn junction portion in which a p-type layer and an n-type layer are pn-bonded; and a passivation layer provided on at least one surface of the semiconductor substrate The heat-treated product of the composition for forming a passivation layer according to any one of <1> to <7>, wherein the electrode is disposed on at least one of the p-type layer and the n-type layer.

<11> A method for producing a solar cell element, comprising: providing at least a part of at least one surface of a semiconductor substrate including a pn junction portion in which a p-type layer and an n-type layer are pn-bonded, such as <1> to < The step of forming a composition layer by using the composition for forming a passivation layer according to any one of the preceding claims; the step of heat-treating the composition layer to form a passivation layer; at least the p-type layer and the n-type layer; The step of arranging the electrodes on one of the layers.

<12> A solar cell comprising: the solar cell element according to <10>; and a wiring material disposed on the electrode of the solar cell element. [Effects of the Invention]

According to one embodiment of the present invention, it is possible to provide a composition for forming a passivation layer which can form a passivation layer which is excellent in patterning property and excellent in passivation effect by a simple method. Moreover, according to an embodiment of the present invention, a semiconductor substrate with a passivation layer including a passivation layer having an excellent passivation effect obtained by using a composition for forming a passivation layer, a method for producing the same, and an excellent conversion efficiency can be provided. Solar cell component and its manufacturing method and solar cell.

Hereinafter, the composition for forming a passivation layer of the present invention, a semiconductor substrate with a passivation layer, a method for producing the same, a solar cell element, a method for producing the same, and a form of a solar cell will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, constituent elements (including element steps and the like) are not essential unless otherwise specified. The present invention is not limited by the numerical values and ranges thereof. In this specification, the term "step" is not only an independent step, but even if it cannot be clearly distinguished from other steps, it is included in the term if the purpose of the step is achieved. Further, the numerical range indicated by "~" indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the case where the content of each component in the composition is a plurality of substances corresponding to the respective components in the composition, unless otherwise specified, the total amount of the plurality of substances present in the composition is indicated. In addition, in the present specification, the term "layer" is used as a plan view, and includes a configuration formed on a part of the shape in addition to the configuration of the entire surface.

<The composition for forming a passivation layer> The composition for forming a first passivation layer of the present embodiment includes a compound represented by the following formula (I) (hereinafter also referred to as "the compound of the formula (I)") and water. Further, the second passivation layer-forming composition of the present embodiment contains a hydrolyzate of the compound of the formula (I). In the present embodiment, the first passivation layer-forming composition and the second passivation layer-forming composition are collectively referred to as a "passivation layer-forming composition". The composition for forming a passivation layer of the present embodiment may further contain other components as needed. By including the above-described components in the composition for forming a passivation layer of the present embodiment, a passivation layer having excellent patterning property and excellent passivation effect can be formed by a simple method.

M(OR ¹ ) _m (I)

In the general formula (I), M represents at least one selected from the group consisting of Al, Nb, Ta, VO, Y, and Hf. R ¹ each independently represents an alkyl group or an aryl group. m represents an integer of 1 to 5.

The inventors of the present invention conducted intensive studies and found that although the mechanism is not clear, the thixotropy of the composition can be improved by causing water to act on the compound of the formula (I). The first passivation layer-forming composition contains the compound of the formula (I) and water, and by reacting water with the compound of the formula (I), the thixotropic ratio of the composition for forming a passivation layer can be improved. On the other hand, the second passivation layer-forming composition contains a hydrolyzate of the compound of the formula (I), which can be produced by allowing water to act on the compound of the formula (I). In the same manner as the first passivation layer-forming composition, the second passivation layer-forming composition causes water to act on the compound of the formula (I), so that the composition ratio of the passivation layer-forming composition is improved. As a result, it is estimated that the composition for forming a passivation layer of the present embodiment is excellent in pattern formability. In the composition for forming a passivation layer of the present embodiment, the thixotropy is improved by acting on the compound of the formula (I), and the composition of the composition layer formed by imparting the composition for forming a passivation layer onto the semiconductor substrate is stable. The properties are further improved, and it becomes possible to form a passivation layer in a desired shape in a region where the composition layer is formed. Therefore, in the composition for forming a passivation layer of the present embodiment, at least one of a thixotropic agent and a resin to be described later is not required in order to exhibit a desired thixotropy (hereinafter, at least one of a thixotropic agent and a resin may be used hereinafter) It is called "thixotropic agent or the like", or even if a thixotropic agent or the like is used, the amount of addition can be reduced as compared with the conventional composition for forming a passivation layer. When a passivation layer is formed using a composition for forming a passivation layer containing a thixotropic agent or the like made of an organic material, the thixotropic agent or the like is thermally decomposed and scattered from the passivation layer by a step of performing a degreasing treatment. However, even if the step of performing the degreasing treatment is carried out, a thermal decomposition product such as a thixotropic agent remains as an impurity in the passivation layer, and the thermal decomposition product such as a thixotropic agent remains, which deteriorates the characteristics of the passivation layer. phenomenon. On the other hand, in the case where a passivation layer is formed using a composition for forming a passivation layer containing a thixotropic agent composed of an inorganic material, the thixotropic agent does not scatter and remains in the passivation layer even after the heat treatment (calcination) step. in. There is a phenomenon in which the remaining thixotropic agent causes deterioration in characteristics of the passivation layer. On the other hand, in the composition for forming a passivation layer of the present embodiment, water acts on the compound of the formula (I), and thus water or a hydrolyzate of the compound of the formula (I) acts as a thixotropic agent. In the heat treatment (calcination) step or the like performed in the case where the passivation layer is formed using the composition for forming a passivation layer, water is more likely to scatter from the passivation layer than the conventional thixotropic agent or the like. Therefore, it is difficult to cause a decrease in the passivation effect of the passivation layer due to the presence of the residue in the passivation layer.

In the present specification, the passivation effect of the semiconductor substrate can be measured by using a device such as WT-2000PVN manufactured by the Japanese company Semirabe, and the effective life of a minority carrier in the semiconductor substrate on which the passivation layer is formed is measured by the microwave reflection photoconduction attenuation method. And evaluate.

Here, the effective lifetime τ can be expressed by the following formula (A) by the body life τ _b inside the semiconductor substrate and the surface life τ _{s of the} surface of the semiconductor substrate. When the surface level density of the surface of the semiconductor substrate is small, τ _s becomes long, and as a result, the effective lifetime τ becomes long. Further, defects such as dangling bonds in the semiconductor substrate are reduced, and the life of the body τ _{b is} increased to increase the effective life τ. That is, the interface characteristics of the passivation layer and the semiconductor substrate and the internal characteristics of the semiconductor substrate such as dangling bonds can be evaluated by measuring the effective lifetime τ.

1/τ=1/τ _b +1/τ _s (A)

In addition, the longer the effective life, the slower the recombination speed of a few carriers. Further, by using a semiconductor substrate having a long effective life to form a solar cell element, conversion efficiency can be improved.

(Compound represented by the formula (I) and a hydrolyzate thereof) The first passivation layer-forming composition contains at least one of the compounds of the formula (I). Further, the second passivation layer-forming composition contains at least one hydrolyzate of the compound of the formula (I). By including at least one of the compounds of the formula (I) or a hydrolyzate thereof in the composition for forming a passivation layer of the present embodiment, a passivation layer having an excellent passivation effect can be formed. The reason for this can be considered as follows.

A metal oxide formed by heat-treating (calcining) a composition for forming a passivation layer containing a compound of the formula (I) or a hydrolyzate thereof has a defect of a metal atom or an oxygen atom, and a fixed charge is likely to be generated. The fixed charge can reduce the concentration of a minority carrier by generating an electric charge in the vicinity of the interface of the semiconductor substrate, and as a result, the carrier recombination speed at the interface is suppressed, and an excellent passivation effect is obtained.

Here, the state of the passivation layer in which a fixed charge is generated on the semiconductor substrate can be achieved by an electron energy loss spectroscopy (EELS, Electron Energy Loss Spectroscopy) using a scanning transmission electron microscope (STEM, Scanning Transmission Electron Microscope). The analysis was conducted to study the combination pattern to evaluate the cross section of the semiconductor substrate. Further, by measuring the X-ray diffraction spectrum (XRD, X-ray diffraction), the crystal phase in the vicinity of the interface of the passivation layer was confirmed. Further, the fixed charge of the passivation layer can be evaluated by a Capacitance Voltage Measurement (CV method).

In the general formula (I), M is at least one selected from the group consisting of Al, Nb, Ta, VO, Y, and Hf, self-passivation effect, pattern formation property of the composition for forming a passivation layer, and preparation of passivation From the viewpoint of workability in the composition for forming a layer, M is preferably at least one selected from the group consisting of Al, Nb, Ta, and Y, and is considered from the viewpoint of thixotropy of the composition for forming a passivation layer. More preferably, Nb.

In the formula (I), R ¹ each independently represents an alkyl group or an aryl group, preferably an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 14 carbon atoms, more preferably 1 to 8 carbon atoms. Further, the alkyl group is more preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group represented by R ¹ may be linear or branched. Specific examples of the alkyl group represented by R ¹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, second butyl group, tert-butyl group, hexyl group, octyl group, and ethyl group. Base and so on. Specific examples of the aryl group represented by R ¹ include a phenyl group. The alkyl group and the aryl group represented by R ¹ may have a substituent, and examples of the substituent include a methyl group, an ethyl group, an isopropyl group, an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group and the like. Among them, from the viewpoint of reactivity with water and a passivation effect, R ^{1 is} preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, more preferably an unsubstituted alkyl group having 1 to 4 carbon atoms. .

In the formula (I), m represents an integer of 1 to 5. Here, from the viewpoint of reactivity with water, when M is Al, m is preferably 3; in the case where M is Nb, m is preferably 5; and M is Ta. In the case, m is preferably 5; in the case where M is VO, m is preferably 3; in the case where M is Y, m is preferably 3; and in the case where M is Hf Preferably, m is 4.

The compound of the formula (I) is preferably at least one selected from the group consisting of Al, Nb, Ta and Y, and R ¹ is an unsubstituted alkyl group having 1 to 4 carbon atoms, and m is 1 to 5 The integer is more preferably M is Nb, R ¹ is an unsubstituted alkyl group having 1 to 4 carbon atoms, and m is 5.

The state of the compound of formula (I) may be either solid or liquid at 25 °C. The compound of the formula (I) is considered from the viewpoints of the storage stability of the composition for forming a passivation layer of the present embodiment, the miscibility with water, and the mixing property in the case of using the compound represented by the formula (II) described later. It is preferred to be a liquid at 25 °C.

Specific examples of the compound of the formula (I) include aluminum methoxide, aluminum ethoxide, aluminum isopropoxide, aluminum n-propoxide, aluminum n-butoxide, aluminum tributoxide, and aluminum isobutoxide. , methoxy oxime, ethoxy ruthenium, isopropoxy oxime, n-propoxy ruthenium, n-butoxy ruthenium, tert-butoxy ruthenium, isobutoxy ruthenium, methoxy ruthenium, ethoxylate Bismuth, isopropoxy oxime, n-propoxy oxime, n-butoxy ruthenium, tert-butoxy ruthenium, isobutoxy ruthenium, methoxy ruthenium, ethoxy ruthenium, isopropoxy oxime, positive Propyl fluorene, n-butoxy fluorene, tert-butoxy fluorene, isobutoxy fluorene, oxymethoxy vanadium, oxyethoxy vanadium, oxyisopropoxy vanadium, oxy-n-propyl Vanadium oxide, oxy-n-butoxy vanadium, oxyt-butoxy vanadium, oxyisobutoxy vanadium, methoxy ruthenium, ethoxy ruthenium, isopropoxy oxime, n-propoxy oxime , n-butoxy fluorene, tert-butoxy fluorene, isobutoxy fluorene, etc., among which preferred are aluminum ethoxide, aluminum isopropoxide, aluminum n-butoxide, ruthenium ethoxylate, and n-propyl Oxime, n-butoxy fluorene, ethoxy hydrazine, n-propoxy fluorene, n-butoxy fluorene, isopropyl Oxyquinone, and n-butoxyfluorene.

Further, the compound of the formula (I) can be used as a manufacturer, and a commercially available product can also be used. Commercially available products include, for example, pentamethoxyindole, pentaethoxy anthracene, pentaisopropoxy fluorene, penta-n-propoxy fluorene, penta-isobutoxy fluorene, and quinone. Butoxy oxime, penta-butoxide, pentamethoxy oxime, pentaethoxy ruthenium, pentaisopropoxy ruthenium, penta-n-propoxy ruthenium, penta-isobutoxy ruthenium, penta-n-butoxy Base, five second butoxy oxime, five third butoxy ruthenium, trimethoxy oxyvanadium (V), triethoxy oxidized vanadium (V), triisopropoxy oxyvanadium (V), three V-vanadium oxide (V), triisobutoxy oxide vanadium (V), tri-n-butoxy vanadium oxide (V), three second butoxy oxide vanadium (V), tri-tert-butoxy Vanadium oxide (V), triisopropoxy ruthenium, tri-n-butoxy ruthenium, tetramethoxy ruthenium, tetraethoxy ruthenium, tetraisopropoxy ruthenium, tetra-butoxy ruthenium, Beixing Chemical Industry Co., Ltd.'s pentaethoxy ruthenium, pentaethoxy ruthenium, pentoxide ruthenium, n-butoxy ruthenium, tert-butoxy ruthenium, triethoxy oxy vanadium oxide of Nichia Chemical Industry Co., Ltd. Tri-n-propoxy oxide vanadium, tri-n-butoxy oxide vanadium, three different Group vanadium oxide (vanadium oxy triisobutoxide), three-butoxy vanadium oxide.

The compound of the formula (I) can be produced by reacting a halide of a specific metal (M) with an alcohol in the presence of an inert organic solvent, and further adding ammonia or an amine to remove the halogen (Japanese Patent Laid-Open No. 63- A known production method such as No. 227 593 and Japanese Patent Laid-Open No. Hei No. 3-291247.

A compound having a chelate structure can also be obtained by mixing a part of the compound of the formula (I) with a compound having a specific structure of two carbonyl groups described below, and is included in the composition for forming a passivation layer of the present embodiment.

The presence of the chelate structure in the compound represented by the formula (I) can be confirmed by a commonly used analytical method. For example, it can be confirmed using an infrared spectroscopic spectrum, a nuclear magnetic resonance spectrum, a melting point, or the like.

The content of the compound of the formula (I) contained in the composition for forming a first passivation layer can be appropriately selected as needed. The content of the compound of the formula (I) is from 0.1% by mass to 80% by mass, preferably 0.5% by mass, based on the reactivity of the water and the passivation effect. ～70% by mass, more preferably 1% by mass to 60% by mass, still more preferably 1% by mass to 50% by mass.

The content rate of the hydrolyzate of the compound of the formula (I) contained in the second passivation layer-forming composition can be appropriately selected as needed. From the viewpoint of the passivation effect, the content of the hydrolyzate of the compound of the formula (I) can be 0.1% by mass to 80% by mass, preferably 0.5% by mass to 70% by mass in the second passivation layer-forming composition. % is more preferably 1% by mass to 60% by mass, still more preferably 1% by mass to 50% by mass. Further, in the present embodiment, the "hydrolyzate of the compound of the formula (I)" means a decomposition product of hydrolysis of the compound of the formula (I) obtained by adding water to the compound of the formula (I), in the formula (I) The compound of the formula (I) which does not react with water may remain in the hydrolyzate of the compound, and water which does not react with the compound of the formula (I) may remain.

(Water) The first passivation layer forming composition contains water. When the first passivation layer-forming composition contains water, it is a composition for forming a passivation layer having excellent pattern formability. The reason for this can be considered as follows.

Water reacts with at least a part of the compound of the formula (I) in the first passivation layer-forming composition. The hydrolyzate of the compound of the formula (I) as a metal compound formed by reacting water with the compound of the formula (I) forms a network by metal compounds. Further, if the composition for forming a passivation layer flows, the mesh is liable to collapse, and if it is again in a stationary state, a mesh is formed again. This mesh increases the viscosity at the time of the composition for forming a passivation layer at rest, and lowers the viscosity at the time of flow. As a result, the composition for forming a passivation layer exhibits thixotropy required for pattern formation.

A passivation layer of a desired shape can be formed by using a composition for forming a passivation layer having excellent pattern formability. Therefore, it is possible to manufacture an excellent semiconductor substrate with a passivation layer, a solar cell element, and a solar cell.

The state of the water can be either solid or liquid. From the viewpoint of the miscibility with the compound of the formula (I), it is preferred that water is a liquid.

The content ratio of water contained in the composition for forming a first passivation layer can be appropriately selected as needed. The content of water in the first passivation layer-forming composition is 0.01% by mass or more, preferably 0.03% by mass or more, more preferably from the viewpoint of imparting thixotropy to the first passivation layer-forming composition. It is preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more. In addition, the content of water in the first passivation layer-forming composition is 0.01% by mass to 80% by mass, preferably 0.03% by mass to 70% by mass, from the viewpoint of the patterning property and the passivation effect. More preferably, it is 0.05% by mass to 60% by mass, and still more preferably 0.1% by mass to 50% by mass.

Further, the second passivation layer forming composition may contain water. The content ratio of water contained in the second passivation layer-forming composition can be appropriately selected as needed. The content of water in the second passivation layer-forming composition is 0.01% by mass or more, preferably 0.03% by mass or more, from the viewpoint of imparting thixotropy to the second passivation layer-forming composition. It is preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more. The content of water in the second passivation layer-forming composition is 0.01% by mass to 80% by mass, preferably 0.03% by mass to 70% by mass, more preferably from 0.03 to 70% by mass, more preferably from the viewpoint of the patterning property and the passivation effect. It is preferably from 0.05% by mass to 60% by mass, and more preferably from 0.1% by mass to 50% by mass.

The amount of water which acts on the compound for formula (I) in the composition for forming a passivation layer can be calculated from the amount of the alcohol which is free from the compound of the formula (I). When water is allowed to act on the compound of formula (I), the alcohol, i.e., R ¹ OH, is freed from the compound of formula (I). The amount of free alcohol is proportional to the number of functional groups of the compound of formula (I) to which water acts. Therefore, the amount of water acting on the compound of the formula (I) can be calculated by measuring the amount of the free alcohol. The measurement of the amount of free alcohol can be confirmed, for example, by gas chromatography mass spectrometry (GC-MS).

The content of the alcohol contained in the composition for forming a passivation layer, that is, the free R ¹ OH is preferably 0.5% by mass to 70% by mass, more preferably 1% by mass to 60% by mass, still more preferably 1% by mass to 50% by mass.

(Compound represented by the formula (II)) The composition for forming a passivation layer of the present embodiment may contain at least one of the compounds represented by the following formula (II) (hereinafter referred to as "organoaluminum compound").

[Chemical 2]

In the formula (II), R ² each independently represents an alkyl group. n represents an integer of 1 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 represent a hydrogen atom or an alkyl group.

The composition for forming a passivation layer of the present embodiment can further improve the passivation effect by including the organoaluminum compound. It can be considered as described below.

The organoaluminum compound includes a compound called an aluminum alkoxide, an aluminum chelate compound or the like, and preferably has an aluminum chelate structure in addition to the aluminum alkoxide structure. Further, as described in Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi, Vol. 97, pp. 369 to 399 (1989), the organoaluminum compound is oxidized by heat treatment (calcination). Aluminum (Al ₂ O ₃ ). At this time, since the formed alumina is likely to be in an amorphous state, it is easy to form a 4-coordinate alumina layer in the vicinity of the interface with the semiconductor substrate, and it is possible to have a large negative fixed charge due to the 4-coordinate alumina. At this time, as a result of being combined with an oxide derived from a compound of the formula (I) having a fixed charge or a hydrolyzate thereof, a passivation layer having an excellent passivation effect can be formed as a result.

In addition to the above, by combining the compound of the formula (I) or a hydrolyzate thereof with the organoaluminum compound as in the present embodiment, the passivation effect is further increased in the passivation layer due to the respective effects. Further, by heat-treating (calcining) in a state in which the compound of the formula (I) or a hydrolyzate thereof is mixed with the organoaluminum compound, the composite of the metal (M) and aluminum (Al) contained in the compound of the formula (I) can be improved. The physical properties such as the reactivity of the metal alkoxide and the vapor pressure are improved as the passivation layer of the heat-treated product (calcined product), and as a result, the passivation effect is further increased.

In the formula (II), R ² each independently represents an alkyl group, preferably an alkyl group having 1 to 8 carbon atoms, more 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 group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, second butyl group, tert-butyl group, hexyl group, octyl group, and ethyl group. Base and so on. Among them, from the viewpoint of storage stability and passivation effect, the alkyl group represented by R ² is preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, more preferably an unsubstituted carbon number of 1 to 4. Alkyl.

In the formula (II), n represents an integer of 1 to 3. From the viewpoint of storage stability, n is preferably 1 or 3, and more preferably 1 from the viewpoint of solubility. Further, X ² and X ³ each independently represent an oxygen atom or a methylene group. From the viewpoint of storage stability, it is preferred that at least one of X ² and X ³ is an oxygen atom. R ³ , R ⁴ and R ⁵ in the formula (II) each independently represent a hydrogen atom or an alkyl group. 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 is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms. Specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a second butyl group, a tert-butyl group, a hexyl group, an octyl group, an ethylhexyl group and the like.

Among them, R ³ and R ^{4 are} preferably independently a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or carbon, from the viewpoints of storage stability and passivation effect. An unsubstituted alkyl group of 1 to 4 is used. Further, from the viewpoints of storage stability and passivation effect, R ^{5 is} preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or a carbon number of 1 to 4 Substituted alkyl.

From the viewpoint of storage stability, the organoaluminum compound is preferably a compound wherein n is an integer of from 1 to 3, and each of R ^{5 is} independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

From the viewpoint of storage stability and passivation effect, the organoaluminum compound is preferably a compound wherein n is an integer of 1 to 3, and R ^{2 is} independently an alkyl group having 1 to 4 carbon atoms, and at least X ² and X ^{3 are present} . One is an oxygen atom, and each of R ³ and R ^{4 is} independently a hydrogen 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. More preferably, the organoaluminum compound is a compound wherein n is an integer of 1 to 3, R ^{2 is} independently an unsubstituted alkyl group having 1 to 4 carbon atoms, and at least one of X ² and X ³ is an oxygen atom. R ³ or R ⁴ bonded to the oxygen atom is an alkyl group having 1 to 4 carbon atoms, and in the case where X ² or X ³ is a methylene group, the R ³ or R to which the methylene group is bonded ⁴ is a hydrogen atom, and R ⁵ is a hydrogen atom.

In addition, examples of the organoaluminum compound in which n is an integer of 1 to 3 represented by the formula (II) include ethyl acetacetate aluminum diisopropylate and aluminum tris(ethyl acetate).

Further, the organoaluminum compound in which n is an integer of 1 to 3 represented by the formula (II) can be used as a manufacturer, and a commercially available product can also be used. Commercially available products include, for example, trade names ALCH, ALCH-50F, ALCH-75, ALCH-TR, ALCH-TR-20, and the like.

Further, the organoaluminum compound in which n is an integer of 1 to 3 represented by the formula (II) can be produced by mixing the aluminum trialkoxide with a compound having a specific structure of two carbonyl groups described below. Further, a commercially available aluminum chelate compound can also be used. When the aluminum trialkoxide is mixed with a compound having a specific structure of two carbonyl groups, at least a part of the alkoxide group of the aluminum trialkoxide is substituted with a compound of a specific structure to form an aluminum chelate structure. At this time, a liquid medium may be present as needed, and heat treatment, addition of a catalyst, or the like may be performed. By replacing at least a part of the aluminum alkoxide structure with the aluminum chelate structure, the stability of the organoaluminum compound with respect to hydrolysis and polymerization can be improved, and the storage stability of the composition for forming a passivation layer including the same can be further improved. .

From the viewpoint of reactivity and storage stability, the compound having a specific structure of two carbonyl groups is preferably selected from the group consisting of a β-diketone compound, a β-ketoester compound, and a malonic acid diester. At least one of them. Specific examples of the compound having a specific structure of two carbonyl groups include acetamidineacetone, 3-methyl-2,4-pentanedione, 2,3-pentanedione, and 3-ethyl-2,4- Pentanedione, 3-butyl-2,4-pentanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 2,6-dimethyl-3,5-g a β-diketone compound such as diketone or 6-methyl-2,4-heptanedione, ethyl acetonitrile acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, acetamidine Isobutyl acetate, n-butyl acetate, n-butyl acetate, n-butyl acetate, n-amyl acetate, isoamyl acetate, n-hexyl acetate, n-octyl acetate, acetonitrile N-heptyl ester, acetonitrile-3-pentyl acetate, ethyl 2-ethyl decyl heptanoate, ethyl 2-methylacetate, ethyl 2-butylacetate, ethyl hexylacetate, Ethyl 4,4-dimethyl-3-oxoethoxyvalerate, ethyl 4-methyl-3-oxoethoxyvalerate, ethyl 2-ethylacetate, 4-methyl-3- Methyl oxetanoate, ethyl 3-oxohexanoate, ethyl 3-oxoethoxyvalerate, methyl 3-oxovalerate, methyl 3-oxohexanoate, 3- Ethyl o-heptanoheptate, methyl 3-oxoheptanoate a β-ketoester compound such as methyl 4,4-dimethyl-3-oxovalerate, dimethyl malonate, diethyl malonate, di-n-propyl malonate, malonic acid Diisopropyl ester, di-n-butyl malonate, di-tert-butyl malonate, dihexyl malonate, tert-butyl malonate, diethyl malonate, ethyl Diethyl malonate, diethyl isopropylmalonate, diethyl n-butylmalonate, diethyl second butyl malonate, diethyl isobutylmalonate, 1- A malonic acid diester such as diethyl dimethyl malonate or the like.

The number of aluminum chelate structures can be controlled, for example, by appropriately adjusting the mixing ratio of the aluminum trialkoxide to a compound having a specific structure of two carbonyl groups. Further, a compound having a desired structure may be appropriately selected from commercially available aluminum chelate compounds.

In the organoaluminum compound, from the viewpoint of self-passivation effect and compatibility with a solvent contained as necessary, it is particularly preferred to use ethyl acetate, aluminum diisopropylate and aluminum triisopropoxide. At least one of the groups formed is more preferably ethylacetate ethylaluminum diisopropylate.

The presence of the aluminum chelate structure in the organoaluminum compound can be confirmed by an analytical method generally used. For example, it can be confirmed using an infrared spectroscopic spectrum, a nuclear magnetic resonance spectrum, a melting point, or the like.

The organoaluminum compound may be in the form of a liquid or a solid, and is not particularly limited. From the viewpoint of self-passivation effect and storage stability, the homogeneity of the formed passivation layer can be further improved by using the stability at normal temperature (25 ° C) and the organoaluminum compound having good solubility or dispersibility. The desired passivation effect is stably obtained.

When the organoaluminum compound is contained in the composition for forming a passivation layer of the present embodiment, the content of the organoaluminum compound is not particularly limited. In particular, the content of the organoaluminum compound when the total content of the compound of the formula (I) or the hydrolyzate thereof and the organoaluminum compound is 100% by mass is preferably 0.5% by mass to 80% by mass, more preferably 1%. The mass% to 75% by mass, more preferably 2% by mass to 70% by mass, particularly preferably 3% by mass to 70% by mass. When the content of the organoaluminum compound is 0.5% by mass or more, the storage stability of the composition for forming a passivation layer tends to be improved. In addition, when the organoaluminum compound is 80% by mass or less, the passivation effect tends to be improved.

When the organic aluminum compound is contained in the composition for forming a passivation layer of the present embodiment, the content of the organoaluminum compound in the composition for forming a passivation layer can be appropriately selected as needed. The content of the organoaluminum compound is from 0.1% by mass to 60% by mass, preferably from 0.5% by mass to 55% by mass, based on the storage stability and the passivation effect, and more preferably from 0.5% by mass to 55% by mass. It is preferably from 1% by mass to 50% by mass, and more preferably from 1% by mass to 45% by mass.

(Liquid Medium) The composition for forming a passivation layer of the present embodiment may also contain a liquid medium (solvent or dispersion medium). By including the liquid medium in the composition for forming a passivation layer, the adjustment of the viscosity is facilitated, the impartability is further improved, and a more uniform passivation layer can be formed. The liquid medium is not particularly limited and may be appropriately selected as needed. Among them, a liquid medium which can dissolve a compound of the formula (I) and an organoaluminum compound which is added as needed to provide a uniform solution, more preferably contains at least one of organic solvents. The "liquid medium" means a medium in a state of being liquid at room temperature (25 ° C).

Specific examples of the liquid medium include acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl isopropyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, and methyl n-amyl ketone. , methyl n-hexyl ketone, diethyl ketone, di-n-propyl ketone, diisobutyl ketone, trimethyl fluorenone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentane Ketone solvent such as ketone or acetone acetone, diethyl ether, methyl ethyl ether, methyl n-propyl ether, diisopropyl ether, tetrahydrofuran, methyl tetrahydrofuran, dioxane, dimethyl dioxane, ethylene Alcohol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl Ether, diethylene glycol methyl-n-propyl ether, diethylene glycol methyl-n-butyl ether, diethylene glycol di-n-propyl ether, diethylene glycol di-n-butyl ether, diethylene glycol methyl - n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl-n-butyl ether, triethylene glycol di-n-butyl ether , triethylene glycol methyl-n-hexyl ether, tetraethylene glycol dimethyl , tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol methyl-n-butyl ether, tetraethylene glycol di-n-butyl ether, tetraethylene glycol methyl-n-hexyl ether, Tetraethylene glycol di-n-butyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol di-n-butyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol methyl ethyl ether, Dipropylene glycol methyl-n-butyl ether, dipropylene glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether, tripropylene glycol methyl ethyl Ether, tripropylene glycol methyl-n-butyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol methyl-n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetrapropylene glycol methyl ethyl ether, tetrapropylene glycol Ether solvent such as butyl-n-butyl ether, tetrapropylene glycol methyl-n-hexyl ether or tetrapropylene glycol di-n-butyl ether, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, acetic acid Isobutyl ester, second butyl acetate, n-amyl acetate, second amyl acetate, acetic acid -3-methoxybutyl ester, methyl amyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 2-(2-butoxyethoxy)ethyl acetate, Benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, decyl acetate, methyl acetate, ethyl acetate, diethylene glycol methyl ether, diethylene glycol monoethyl ether, acetic acid Propylene glycol methyl ether, dipropylene glycol diethyl ether, ethylene glycol diacetate, methoxytriethylene glycol acetate, isoamyl acetate, ethyl propionate, n-butyl propionate, isoamyl propionate, diethyl oxalate Ester, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, ethylene glycol methyl ether propionate, ethylene glycol ether propionate, ethylene glycol methyl ether acetate Ester, ethylene glycol ether acetate, propylene glycol methyl ether acetate, propylene glycol diethyl ether acetate, propylene glycol propyl ether acetate, γ-butyrolactone, γ-valerolactone and other ester solvents, acetonitrile, N-A Pyrrolidone, N-ethylpyrrolidone, N-n-propylpyrrolidone, N-n-butylpyrrolidone, N-n-hexylpyrrolidone, N-cyclohexylpyrrolidone, N,N - dimethylformamide, N, Aprotic polar solvents such as N-dimethylacetamide, dimethylhydrazine, dichloromethane, chloroform, dichloroethane, benzene, toluene, xylene, hexane, octane, ethylbenzene, 2 -hydrophobic organic solvent such as ethylhexanoic acid, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, second butanol, third butanol, n-pentanol, isoamyl alcohol, 2 -methylbutanol, second pentanol, third pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, second hexanol, 2-ethylbutanol, second heptanol , n-octanol, 2-ethylhexanol, second octanol, n-nonanol, n-nonanol, second-undecanol, trimethylnonanol, second-tetradecanol, second- Heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexanol, benzyl alcohol, ethylene glycol, 1,2-propanediol, 1,3-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol Alcohol solvent such as tripropylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether Diethylene glycol mono-n-hexyl ether, ethoxy triethylene glycol ether, tetraethylene glycol mono-n-butyl ether , propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether and other glycol monoether solvent, terpinene, terpineol, laurylene, allo-ocimene, limonene, dipentene A terpene solvent such as terpene, decyl ketone, basilene or water celery. These liquid mediums may be used alone or in combination of two or more.

In particular, the liquid medium preferably contains at least one selected from the group consisting of a terpene solvent, an ester solvent, and an alcohol solvent, from the viewpoint of impartability to a semiconductor substrate and pattern formation property, and more preferably At least one selected from the group consisting of terpene solvents is contained.

When the composition for forming a passivation layer contains a liquid medium, the content of the liquid medium can be determined in consideration of impartability, pattern formation property, and storage stability. For example, from the viewpoint of the impartability of the composition and the pattern formation property, the content of the liquid medium is preferably from 5% by mass to 98% by mass based on the total mass of the composition for forming a passivation layer, more preferably 10% by mass. Mass% to 95% by mass.

(Resin) The composition for forming a passivation layer of the present embodiment may further contain at least one of resins. By including the resin, the shape stability of the composition layer formed by applying the composition for forming a passivation layer of the present embodiment to the semiconductor substrate is further improved, and the desired shape can be formed in the region where the composition layer is formed. A passivation layer is formed.

The kind of the resin is not particularly limited. When the composition for forming a passivation layer of the present embodiment is applied to a semiconductor substrate, the resin can be adjusted to have a viscosity in a range in which a favorable pattern can be formed. Specific examples of the resin include polyvinyl alcohol, polypropylene decylamine, polypropylene decylamine derivative, polyvinyl decylamine, polyvinyl decylamine derivative, polyvinylpyrrolidone, polyethylene oxide, and polyethylene oxide. Alkane derivatives, polysulfonic acids, polypropylene decylamine sulfonic acids, cellulose, cellulose derivatives (carboxymethyl cellulose, hydroxyethyl cellulose, cellulose ether, etc.), gelatin , gelatin derivatives, starch, starch derivatives, sodium alginate, sodium alginate derivatives, Sanxian gum, Sanxian gum derivatives, guar gum, guar gum derivatives, scleroglucan, Hard glucan derivative, tragacanth, xanthan gum derivative, dextrin, dextrin derivative, (meth)acrylic resin, (meth) acrylate resin (alkyl (meth) acrylate resin, (a Base) dimethylaminoethyl acrylate resin, etc., butadiene resin, styrene resin, decane resin, copolymers of these, and the like. These resins may be used alone or in combination of two or more. In the present embodiment, the "(meth)acrylic group" means an acryl group or a methacryl group, and the "(meth)acrylate" means an acrylate or a methacrylate.

From the viewpoints of storage stability and pattern formation, it is preferred to use a neutral resin which does not have an acidic or basic functional group, and the viscosity can be easily adjusted even in a small amount. From the viewpoint of thixotropy, it is more preferable to use a cellulose derivative. Further, the molecular weight of the resins is not particularly limited, and is preferably adjusted in view of the desired viscosity as a composition for forming a passivation layer. The weight average molecular weight of the resin is preferably from 1,000 to 10,000,000, more preferably from 1,000 to 5,000,000, from the viewpoints of storage stability and pattern formation. Further, the weight average molecular weight of the resin is determined by conversion using a calibration curve of standard polystyrene based on a molecular weight distribution measured by Gel Permeation Chromatography (GPC).

In the case where the composition for forming a passivation layer of the present embodiment contains a resin, the content of the resin in the composition for forming a passivation layer can be appropriately selected as needed. For example, the content of the resin is preferably from 0.1% by mass to 50% by mass based on the total mass of the composition for forming a passivation layer. From the viewpoint of exhibiting thixotropy in which pattern formation is more easily formed, the content of the resin is more preferably 0.2% by mass to 25% by mass, still more preferably 0.5% by mass to 20% by mass, and particularly preferably 0.5% by mass. % to 15% by mass. Further, since the composition for forming a passivation layer of the present embodiment is excellent in thixotropic properties, the necessity of exhibiting thixotropy by a resin is not high. Therefore, the content of the resin contained in the composition for forming a passivation layer of the present embodiment is preferably 0.5% by mass or less, more preferably 0.2% by mass or less, still more preferably 0.1% by mass or less, particularly preferably It is essentially free of resin.

(Other components) The composition for forming a passivation layer of the present embodiment may further contain other components generally used in the field, in addition to the above components. The composition for forming a passivation layer of the present embodiment may also contain an acidic compound or a basic compound. When the composition for forming a passivation layer contains an acidic compound or a basic compound, the content of the acidic compound or the basic compound is preferably 1 in the composition for forming a passivation layer from the viewpoint of storage stability. The mass% or less is more preferably 0.1% by mass or less. Examples of the acidic compound include Blenster acid and Lewis acid. Specific examples thereof include inorganic acids such as hydrochloric acid and nitric acid, and organic acids such as acetic acid. Further, examples of the basic compound include a Bruce base and a Lewis base. Specific examples of the basic compound include inorganic bases such as alkali metal hydroxides and alkaline earth metal hydroxides, and organic bases such as trialkylamine and pyridine.

Further, examples of the other components include a plasticizer, a dispersant, a surfactant, a thixotropic agent, another metal alkoxide compound, and a high boiling point material. Among them, it is preferred to contain at least one selected from the group consisting of a thixotropic agent. By including at least one selected from the group consisting of a thixotropic agent, the shape stability of the composition layer formed by imparting the composition for forming a passivation layer of the present embodiment onto the semiconductor substrate can be further improved, and the composition can be formed. The region of the layer forms a passivation layer in a desired shape.

The thixotropic agent may, for example, be a fatty acid guanamine, a polyalkylene glycol compound, an organic filler, an inorganic filler or the like. The polyalkylene glycol compound may, for example, be a compound represented by the following formula (III).

R ⁶ -(OR ⁸ ) _n -OR ⁷ ···(III)

In the 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. In addition, R ⁸ in a plurality of existing (OR ⁸ ) may be the same or different.

Examples of the fatty acid guanamine include compounds represented by the following general formula (1), formula (2), formula (3), and formula (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)

In the formula (1), the formula (2), the formula (3) and the formula (4), R ⁹ and R ¹¹ each independently represent an alkyl group or an alkenyl group having 1 to 30 carbon atoms, and R ¹⁰ represents carbon. A number of from 1 to 10 alkyl groups. R ⁹ and R ¹¹ may be the same or different.

The organic filler may, for example, be an acrylic resin, a cellulose resin, a polystyrene resin or the like.

Examples of the inorganic filler include particles of cerium oxide, aluminum hydroxide, aluminum nitride, cerium nitride, aluminum oxide, zirconium oxide, cerium carbide, glass, and the like.

The volume average particle diameter of the organic filler or the inorganic filler is preferably from 0.01 μm to 50 μm. In the present embodiment, the volume average particle diameter of the filler can be measured by a laser diffraction scattering method.

Examples of the other metal alkoxide compound include a titanium alkoxide, a zirconium alkoxide, a decyl alkoxide, and the like.

The composition for forming a passivation layer of the present embodiment does not require a thixotropic agent or the like for imparting thixotropic properties, shape stability, or the like, or the amount thereof to be used is reduced. Therefore, the composition for forming a passivation layer of the present embodiment is at 150 ° C. When the drying treatment for 3 hours is carried out, the ratio of the mass after the heat treatment as compared with the conventional composition for forming a passivation layer containing a thixotropic agent or the like is low. This is because water is easily scattered from the composition for forming a passivation layer in comparison with a conventional thixotropic agent or the like by heat treatment at 150 ° C for 3 hours. Specifically, the ratio (M1/M2) calculated by dividing the mass M1 when the composition for forming a passivation layer of the present embodiment is heated at 150 ° C for 3 hours by the mass M2 when not heated is 0.0001. ～0.7, in the range of the solid content, the shear viscosity η1 at a shear rate of 25 ° C of 0.1 s ^-1 divided by the shear viscosity η 2 of a shear rate of 10.0 s ^-1 (η1) /η2) is preferably from 1.05 to 100, more preferably from 1.1 to 50. In addition, the shear viscosity was measured at a temperature of 25 ° C using a rotary shear viscometer equipped with a cone plate (diameter 50 mm, cone angle 1 °). In the present embodiment, the ratio (M1/M2) is preferably 0.0005 to 0.6, more preferably 0.001 to 0.5.

Thixotropic passivation layer according to the present embodiment is formed of 0.1 s ^-1 shear viscosity eta] 1 divided by the shear rate with the shear rate of the composition is 25 deg.] C to shear viscosity η2 10.0 s ^-1 of the calculated ratio (eta] 1 /η2) is preferably from 1.05 to 100, more preferably from 1.1 to 50. Further, the ratio (M1/M2) calculated by dividing the mass M1 when the composition for forming a passivation layer of the present embodiment is heated at 150 ° C for 3 hours by the mass M2 when not heated is preferably 0.0001 to 0.7, more preferably 0.0005 to 0.6, still more preferably 0.001 to 0.5.

(High-boiling material) In the composition for forming a passivation layer of the present embodiment, a high-boiling material may be used together with the resin, or a high-boiling material may be used as a material instead of the resin. The high boiling point material is preferably a compound which is easily vaporized upon heating without requiring degreasing treatment. Further, a high-boiling material is particularly preferable as a high-boiling high-boiling material which can maintain a printed shape after printing and coating. Examples of the material satisfying these include isobornylcyclohexanol.

Isobornylcyclohexanol is commercially available as "Tersorb MTPH" (Japanese Terpene Chemical Co., Ltd., trade name). The isobornylcyclohexanol has a boiling point as high as 308 ° C to 318 ° C, and when it is removed from the composition layer, it is not required to be subjected to a degreasing treatment by heat treatment (calcination) as a resin, and it can be vaporized by heating. Make it disappear. Therefore, most of the solvent contained in the composition for forming a passivation layer and the isobornylcyclohexanol can be removed by a drying step after being applied onto the semiconductor substrate.

When the composition for forming a passivation layer of the present embodiment contains a high boiling point material, the content of the high boiling point material is preferably from 3% by mass to 95% by mass based on the total mass of the composition for forming a passivation layer. It is preferably from 5% by mass to 90% by mass, and more preferably from 7% by mass to 80% by mass.

In addition, the composition for forming a passivation layer of the present embodiment may contain at least one oxide (hereinafter referred to as "specific oxide") selected from the group consisting of Al, Nb, Ta, V, Y, and Hf. Since the specific oxide is an oxide formed by heat-treating (calcining) the compound of the formula (I), it is expected that the passivation layer formed of the composition for forming a passivation layer containing a specific oxide exhibits an excellent passivation effect.

The viscosity of the composition for forming a passivation layer of the present embodiment is not particularly limited, and can be appropriately selected depending on the method of imparting the semiconductor substrate or the like. For example, the viscosity of the composition for forming a passivation layer can be set to 0.01 Pa·s to 100,000 Pa·s. Among them, from the viewpoint of pattern formability, the viscosity of the composition for forming a passivation layer is preferably from 0.1 Pa·s to 10,000 Pa·s. Alternatively, the viscosity can be measured using a rotary shear viscometer at 25 ° C and a shear rate of 1.0 s ^-1 .

The method for producing the composition for forming a passivation layer of the present embodiment is not particularly limited. For example, it can be produced by mixing a compound of the formula (I), water, an organoaluminum compound contained as necessary, a liquid medium, a resin or the like by a mixing method which is usually used. In addition, the content of each component and the content of each component in the composition for forming a passivation layer of the present embodiment can be confirmed by thermal analysis such as TG/DTA, spectral analysis such as NMR or IR, and chromatographic analysis such as HPLC or GPC.

<Semiconductor Substrate with Passivation Layer> The semiconductor substrate with a passivation layer according to the present embodiment includes a semiconductor substrate, and a passivation layer formed of a passivation layer of the present embodiment provided on at least a part of at least one surface of the semiconductor substrate A heat treatment of the composition is used. The semiconductor substrate with a passivation layer of the present embodiment exhibits an excellent passivation effect because it contains a passivation layer as a heat-treated product of the composition for forming a passivation layer of the present embodiment.

The semiconductor substrate is not particularly limited and may be appropriately selected from usual users depending on the purpose. The semiconductor substrate may be one in which a p-type impurity or an n-type impurity is doped (diffused) in ruthenium, osmium or the like. Among them, a ruthenium substrate is preferred. Further, the semiconductor substrate may be a p-type semiconductor substrate or an n-type semiconductor substrate. Among them, from the viewpoint of the passivation effect, a semiconductor substrate in which the surface on which the passivation layer is formed is a p-type layer is preferable. The p-type layer on the semiconductor substrate may be a p-type layer derived from a p-type semiconductor substrate, or may be formed on an n-type semiconductor substrate or a p-type semiconductor substrate as a p-type diffusion layer or a p ⁺ -type diffusion layer. .

Further, the thickness of the semiconductor substrate is not particularly limited and may be appropriately selected depending on the purpose. For example, the thickness of the semiconductor substrate can be set to 50 μm to 1000 μm, preferably 75 μm to 750 μm.

The thickness of the passivation layer formed on the semiconductor substrate is not particularly limited and may be appropriately selected depending on the purpose. For example, it is preferably 5 nm to 50 μm, more preferably 10 nm to 30 μm, still more preferably 15 nm to 20 μm. Further, the average thickness of the passivation layer formed can be measured by an ordinary method using an interferometric film thickness meter (for example, FILMETRICS, F20 film thickness measuring system), and the arithmetic mean value is calculated. And calculate.

The semiconductor substrate with a passivation layer of the present embodiment can be applied to a solar cell element, a light emitting diode element, or the like. For example, a solar cell element excellent in conversion efficiency can be obtained by being applied to a solar cell element.

<Manufacturing Method of Semiconductor Substrate with Passivation Layer> The method for producing a semiconductor substrate with a passivation layer according to the present embodiment includes forming a composition for forming a passivation layer of at least one part of at least one surface of a semiconductor substrate. a step of constituting the layer; a step of subjecting the composition layer to heat treatment (calcination) to form a passivation layer. The manufacturing method may further include other steps as needed. By using the composition for forming a passivation layer of the present embodiment, a passivation layer having excellent patterning property and excellent passivation effect can be formed by a simple method.

In the method for producing a semiconductor substrate with a passivation layer according to the present embodiment, it is preferable to further include a step of providing an alkaline aqueous solution on the semiconductor substrate before the step of forming the composition layer. In other words, it is preferable to clean the surface of the semiconductor substrate with an alkaline aqueous solution before the composition for forming a passivation layer of the present embodiment is applied to the semiconductor substrate. By washing with an alkaline aqueous solution, organic substances, particles, and the like existing on the surface of the semiconductor substrate can be removed, and the passivation effect can be further improved. As a method of washing with an alkaline aqueous solution, a generally known cleaning method using RCA cleaning or the like can be exemplified. For example, the semiconductor substrate can be immersed in a mixed solution of ammonia water and hydrogen peroxide water, and treated at 60 to 80 ° C to remove the organic material and particles and clean the particles. The cleaning time is preferably from 10 seconds to 10 minutes, more preferably from 30 seconds to 5 minutes.

The method of forming the composition layer by providing the composition for forming a passivation layer of the present embodiment on the semiconductor substrate is not particularly limited. For example, a method of imparting the composition for forming a passivation layer of the present embodiment to a semiconductor substrate by using a known coating method or the like can be mentioned. Specific examples thereof include a dipping method, a screen printing method, an inkjet method, a dispenser method, a spin coating method, a brush coating method, a spray method, a doctor blade method, and a roll coating method. From the viewpoint of pattern formation property and productivity, a screen printing method, an inkjet method, and the like are preferable among these.

The amount of the composition for forming a passivation layer of the present embodiment can be appropriately selected depending on the purpose. For example, the thickness of the formed passivation layer can be appropriately adjusted so as to have a desired thickness.

The heat treatment layer (calcined layer) derived from the composition layer is formed by heat-treating (calcining) the composition layer formed of the composition for forming a passivation layer, whereby a passivation layer can be formed on the semiconductor substrate . The heat treatment (calcination) condition of the composition layer can convert the compound of the formula (I) contained in the composition layer and the organoaluminum compound optionally contained into a metal oxide or a composite oxide as a heat-treated product (calcined product). , there is no special limit. In order to effectively provide a fixed charge to the passivation layer, a more excellent passivation effect is obtained. Specifically, the heat treatment (calcination) temperature is preferably from 300 ° C to 900 ° C, more preferably from 450 ° C to 800 ° C. Further, the heat treatment (calcination) time can be appropriately selected depending on the heat treatment (calcination) temperature and the like. For example, it can be set to 0.1 hour to 10 hours, preferably 0.2 hour to 5 hours.

The method for producing a semiconductor substrate with a passivation layer according to the present embodiment may further include a step of forming a passivation layer by heat treatment (calcination) after applying the composition for forming a passivation layer of the present embodiment to a semiconductor substrate. The step of drying the composition layer containing the composition for forming a passivation layer. A passivation layer having a more uniform passivation effect can be formed by including a step of drying the composition layer.

The step of drying the composition layer may be carried out by removing at least a part of the water contained in the composition for forming a passivation layer and at least a part of the liquid medium which may be contained in the composition for forming a passivation layer. limit. The drying treatment can be carried out, for example, at 30 ° C to 250 ° C for 1 minute to 60 minutes, preferably at 40 ° C to 220 ° C for 3 minutes to 40 minutes. Further, the drying treatment can be carried out under normal pressure or under reduced pressure.

When the composition for forming a passivation layer contains a resin, the method for producing a semiconductor substrate with a passivation layer according to the present embodiment may be a step of forming a passivation layer by heat treatment (calcination) after providing a composition for forming a passivation layer. Previously, a step of degreasing the composition layer containing the composition for forming a passivation layer was further included. A passivation layer having a more uniform passivation effect can be formed by including a step of degreasing the composition layer.

The step of degreasing the composition layer is not particularly limited as long as at least a part of the resin contained in the composition for forming a passivation layer can be removed. The degreasing treatment can be carried out, for example, at a temperature of from 250 ° C to 450 ° C for 3 minutes to 120 minutes, preferably at a temperature of from 250 ° C to 450 ° C for 10 minutes to 120 minutes, more preferably The heat treatment is performed at 300 ° C to 400 ° C for 3 minutes to 60 minutes. Further, the degreasing treatment is preferably carried out in the presence of oxygen, more preferably in the atmosphere.

<Solar cell element> The solar cell element of the present embodiment includes a semiconductor substrate including a pn junction portion in which a p-type layer and an n-type layer are pn-bonded, and a passivation layer provided on at least one of the semiconductor substrate. At least a part of the heat treatment of the composition for forming a passivation layer of the present embodiment; and an electrode disposed on at least one of the p-type layer and the n-type layer. The solar cell element of the present embodiment may further include other components as needed. Since the solar cell element of the present embodiment includes the passivation layer formed of the composition for forming a passivation layer of the present embodiment, the conversion efficiency is excellent.

The semiconductor substrate to which the composition for forming a passivation layer of the present embodiment is applied is not particularly limited, and can be appropriately selected from ordinary users depending on the purpose. The semiconductor substrate can be used in the item of the semiconductor substrate with a passivation layer of the present embodiment, and the same can be applied to the user. The surface of the semiconductor substrate provided with the passivation layer of the present embodiment is preferably the back surface of the solar cell element.

Further, the thickness of the passivation layer formed on the semiconductor substrate is not particularly limited and may be appropriately selected depending on the purpose. For example, the average thickness of the passivation layer is preferably 5 nm to 50 μm, more preferably 10 nm to 30 μm, still more preferably 15 nm to 20 μm. The shape and size of the solar cell element of the present embodiment are not limited. For example, it is preferred that the one side is a substantially square shape of 125 mm to 156 mm.

<Manufacturing Method of Solar Cell Element> The method of manufacturing a solar cell element according to the present embodiment includes at least a part of at least one surface of a semiconductor substrate including a pn junction portion in which a p-type layer and an n-type layer are pn-bonded. a step of forming a composition layer by the composition for forming a passivation layer of the present embodiment; a step of forming a passivation layer by heat-treating (calcining) the composition layer; and at least one of the p-type layer and the n-type layer The step of arranging the electrodes on the layer. The method of manufacturing the solar cell element of the present embodiment may further include other steps as needed.

By using the composition for forming a passivation layer of the present embodiment, a solar cell element having excellent conversion efficiency can be produced by a simple method.

A method of arranging electrodes on at least one of a p-type layer and an n-type layer of a semiconductor substrate can be carried out by a commonly used method. For example, an electrode for forming an electrode such as a silver paste or an aluminum paste can be applied to a desired region of the semiconductor substrate, and heat treatment (calcination) can be performed as needed to produce an electrode.

The surface of the semiconductor substrate provided with the passivation layer of the present embodiment may be a p-type layer or an n-type layer. Among them, from the viewpoint of conversion efficiency, a p-type layer is preferable. The details of the method of forming the passivation layer using the composition for forming a passivation layer of the present embodiment are the same as the method of manufacturing the semiconductor substrate with a passivation layer, and preferred embodiments are also the same.

Next, the present embodiment will be described with reference to the drawings. In addition, the size of the member in each figure is a conceptual size, and the relative relationship of the magnitude|size of the member is not limited to this. Further, members having substantially the same functions are denoted by the same reference numerals throughout the drawings, and the description thereof will not be repeated. 1(1) to 1(9) are diagrams showing a step of a schematic diagram showing a method of manufacturing a solar cell element including the passivation layer of the present embodiment. However, the step chart does not impose any limitation on the present invention.

In FIG. 1 (1), the p-type semiconductor substrate 1 is cleaned by an alkaline aqueous solution to remove organic substances, particles, and the like on the surface of the p-type semiconductor substrate 1. Thereby, the passivation effect is further improved. The method of washing with an alkaline aqueous solution can be exemplified by a method generally known as RCA cleaning or the like.

Then, as shown in FIG. 1 (2), the surface of the p-type semiconductor substrate 1 is subjected to alkaline etching or the like to form irregularities (also referred to as "textures") on the surface. Thereby, the reflection of sunlight can be suppressed on the light receiving surface side. In addition, an etching solution containing NaOH and IPA (isopropyl alcohol) can be used in the alkaline etching.

Then, as shown in Fig. 1 (3), the surface of the p-type semiconductor substrate 1 is thermally diffused by phosphorus or the like, and the n ⁺ -type diffusion layer 2 is formed in a thickness of a submicron order, and at the boundary with the p-type body portion. A pn junction is formed.

The method for diffusing phosphorus is, for example, a method in which a treatment is carried out at a temperature of 800 ° C to 1000 ° C for several tens of minutes in a mixed gas atmosphere of phosphorus chlorochloride (POCl ₃ ), nitrogen and oxygen. In this method, phosphorus is diffused by using a mixed gas. Therefore, as shown in Fig. 1 (3), an n ⁺ -type diffusion layer 2 is formed on the back surface and the side surface (not shown) in addition to the light-receiving surface (surface). . Further, a PSG (phosphorite glass) layer 3 is formed on the n ⁺ -type diffusion layer 2. Therefore, side etching is performed to remove the PSG layer 3 and the n ⁺ -type diffusion layer 2 on the side surface.

Thereafter, as shown in Fig. 1 (4), the PSG layer 3 on the light-receiving surface and the back surface is removed using an etching solution such as hydrofluoric acid. Further, as shown in FIG. 1 (5), the back surface is additionally subjected to an etching treatment to remove the n ⁺ -type diffusion layer 2 on the back surface.

Next, as shown in Fig. 1 (6), on the n ⁺ -type diffusion layer 2 on the light-receiving surface, a plasma enhanced chemical vapor deposition (PECVD) method or the like is applied to a thickness of about 90 nm. An anti-reflection film 4 such as tantalum nitride is provided.

Then, as shown in Fig. 1 (7), the composition for forming a passivation layer of the present embodiment is applied to a part of the back surface by screen printing or the like, and then dried at a temperature of 300 ° C to 900 ° C after drying. The passivation layer 5 is formed by heat treatment (calcination).

An example of the formation pattern of the passivation layer on the back surface is shown in FIG. 5 as a schematic plan view. Fig. 7 is a schematic plan view showing an enlarged portion A of Fig. 5; Fig. 8 is a schematic plan view showing an enlarged portion B of Fig. 5; In the case of forming a pattern of the passivation layer shown in FIG. 5, it can be seen from FIG. 7 and FIG. 8 that the portion where the back surface output extraction electrode 7 is formed is removed in the subsequent step, and the p-type semiconductor substrate 1 is exposed as a dot. The pattern forms a passivation layer 5 on the back side. The pattern of the dot-shaped opening portion is preferably defined by a dot diameter (L _a ) and a dot interval (L _b ), and is regularly arranged. The spot diameter (L _a) and the dot pitch (L _b) can be arbitrarily set, but the effects of self-passivating and inhibiting minority carrier recombination viewpoint, preferred is L _a of 5 μm ~ 2 mm and L _b is 10 μm ~ 3 mm, more preferably the L _a is 10 μm ~ 1.5 mm and L _b is 20 μm ~ 2.5 mm, is further more preferably L _a is 20 μm ~ 1.3 mm and L _b is 30 μm ~ 2 mm .

When the composition for forming a passivation layer has excellent pattern formability, the dot pattern of the dot-shaped opening portion arranges the dot diameter (L _a ) and the dot interval (L _b ) more regularly. Therefore, it is possible to form a pattern in which a small number of carriers are recombined to suppress better dot-like openings, and the power generation efficiency of the solar cell element is improved.

Here, a passivation layer forming composition is applied to a portion where the passivation layer is to be formed (a portion other than the dot-shaped opening portion), and heat treatment (baking) is performed to form a passivation layer having a desired shape. On the other hand, the passivation layer forming composition may be applied to the entire surface including the dot-shaped opening, and the passivation layer of the dot-shaped opening portion may be selectively removed by laser irradiation, photolithography, or the like after heat treatment (baking). . In addition, the portion for forming the passivation layer may be selectively coated by masking the portion of the dot-shaped opening portion where the composition for forming the passivation layer is not desired.

Then, as shown in FIG. 1 (8), the silver electrode paste containing the glass particles is formed by applying the light-receiving surface current collecting electrode 8 and the light-receiving surface output extraction electrode 9 to the light-receiving surface by screen printing or the like. 4 is a schematic plan view showing an example of a light receiving surface of a solar cell element. As shown in FIG. 4, the light-receiving surface electrode includes a light-receiving surface current collecting electrode 8 and a light-receiving surface output/extracting electrode 9. In order to secure the light receiving area, it is necessary to suppress the formation area of the light receiving surface electrodes less. Further, from the viewpoint of the electrical resistivity and productivity of the light-receiving surface electrode, it is preferable that the width of the light-receiving surface collecting electrode 8 is 10 μm to 250 μm, and the width of the light-receiving surface output extracting electrode 9 is 100 μm to 2 mm. . Further, although two light-receiving surface output extraction electrodes 9 are provided in FIG. 4, the number of light-receiving surface output extraction electrodes 9 may be three or three from the viewpoint of extraction efficiency (power generation efficiency) of a small number of carriers. 4 roots.

On the other hand, as shown in Fig. 1 (8), the glass electrode-containing aluminum electrode paste for forming the back surface current collecting aluminum electrode 6 and the back surface output extraction electrode 7 are formed by back printing or the like by screen printing or the like. Silver electrode paste of glass particles. 9 is a schematic plan view showing an example of a back surface of a solar cell element. The width of the back surface output extraction electrode 7 is not particularly limited, and the width of the back surface extraction electrode 7 is preferably 100 μm to 10 mm from the viewpoint of the connection property of the wiring material in the subsequent solar cell manufacturing step.

After the electrode paste is applied to the light-receiving surface and the back surface, it is heat-treated (calcined) together with the light-receiving surface and the back surface in the air at a temperature of about 450 ° C to 900 ° C after drying, and the light-receiving surface is formed on the light-receiving surface. The electrode 8 and the light-receiving surface are outputted to the extraction electrode 9, and the back surface current collecting aluminum electrode 6 and the back surface output extraction electrode 7 are formed on the back surface.

After the heat treatment (calcination), as shown in Fig. 1 (9), the glass particles contained in the silver electrode paste forming the light-receiving surface electrode are reacted (burned through) with the anti-reflection film 4 on the light-receiving surface, and the light-receiving surface is received. The electrode (the light-receiving surface current collecting electrode 8 and the light-receiving surface output extracting electrode 9) is electrically connected (ohmic contact) to the n ⁺ -type diffusion layer 2 . On the other hand, in the back surface, in the portion where the semiconductor substrate 1 is exposed as a dot (the portion where the passivation layer 5 is not formed), aluminum in the aluminum electrode paste is diffused into the semiconductor substrate 1 by heat treatment (calcination), This forms the p ⁺ -type diffusion layer 10. In the present embodiment, by using the composition for forming a passivation layer of the present embodiment which is excellent in pattern formability, a passivation layer having excellent passivation effect can be formed by a simple method, and a solar cell element excellent in power generation performance can be produced.

2(10) to 2(18) are diagrams showing a step of the other example of the method of manufacturing the solar cell element including the passivation layer of the present embodiment, and the back surface is n ⁺ by etching treatment. The solar cell element can be produced in the same manner as in Fig. 1 (1) to Fig. 1 (9) except that the back surface is further flattened after the diffusion layer 2 is removed. In the case of planarization, a method of immersing the back surface of the semiconductor substrate in a mixed solution of nitric acid, hydrofluoric acid, and acetic acid or a potassium hydroxide solution can be used.

3(19) to 3(29) are cross-sectional views showing other steps of a method of manufacturing a solar cell element including the passivation layer of the present embodiment. In this method, the steps of forming the texture structure, the n ⁺ -type diffusion layer 2 and the anti-reflection film 4 on the semiconductor substrate 1 (Figs. 3(19) to 3(24)) and Fig. 1(1) to The method of Figure 1 (9) is the same.

After the antireflection film 4 is formed, a composition for forming a passivation layer is applied as shown in Fig. 3 (25). An example of the formation pattern of the passivation layer on the back surface is shown in FIG. 6 as a schematic plan view. In the formation pattern of the passivation layer shown in FIG. 6, the dot-shaped openings are arranged on the entire surface of the back surface, and in the subsequent step, the dot-shaped openings are also arranged in the portion where the rear-side output extraction electrodes are formed.

Then, as shown in FIG. 3 (26), in the back surface, a portion (a portion where the passivation layer 5 is not formed) exposed from the semiconductor substrate 1 diffuses boron or aluminum to form the p ⁺ -type diffusion layer 10. When the p ⁺ -type diffusion layer 10 is formed, when boron is diffused, a method of treating at a temperature of around 1000 ° C in a gas containing boron trichloride (BCl ₃ ) can be used. However, since it is a method of diffusing a gas similarly to the case of using phosphonium chloride, the p ⁺ type diffusion layer 10 is formed on the light-receiving surface, the back surface, and the side surface of the substrate. Therefore, in order to suppress this phenomenon, the following measures are required: The portion other than the opening portion is shielded to prevent diffusion of boron into unnecessary portions of the p-type semiconductor substrate 1 or the like.

Further, when the p ⁺ -type diffusion layer 10 is formed, when aluminum is diffused, a method of applying the aluminum paste to the dot-shaped opening portion and heat-treating it at a temperature of 450 ° C to 900 ° C can be used ( The calcination is performed by diffusing aluminum from the dot-like opening to form the p ⁺ -type diffusion layer 10, and then etching the heat-treated layer (calcined layer) containing the aluminum paste on the p ⁺ -type diffusion layer 10 by hydrochloric acid or the like.

Then, as shown in FIG. 3 (27), aluminum is physically deposited on the entire surface of the back surface, whereby the aluminum electrode 11 for back surface current collection is formed.

Then, as shown in Fig. 3 (28), the silver electrode paste containing the glass particles is formed by applying the light-receiving surface current collecting electrode 8 and the light-receiving surface output extracting electrode 9 to the light-receiving surface by screen printing or the like. A silver electrode paste containing glass particles which is formed on the back surface by screen printing or the like to form the back surface output extraction electrode 7 is applied. The silver electrode paste on the light-receiving surface overlaps with the shape of the light-receiving surface electrode shown in FIG. 4, and the silver electrode paste on the back surface overlaps the shape of the back electrode shown in FIG. 9, and is given a pattern.

After applying the electrode paste to the light-receiving surface and the back surface, respectively, after drying, heat treatment (calcination) is performed together with the light-receiving surface and the back surface in the atmosphere at a temperature of about 450 ° C to 900 ° C, as shown in Fig. 3 (29). The light-receiving surface current collecting electrode 8 and the light-receiving surface output extraction electrode 9 are formed on the light-receiving surface, and the back surface output extraction electrode 7 is formed on the back surface. At this time, the light-receiving surface electrode and the n ⁺ -type diffusion layer 2 are electrically connected to the light-receiving surface, and the back surface current collecting aluminum electrode 11 and the back surface output extraction electrode 7 which are formed by vapor deposition are electrically connected to the back surface.

<Solar cell> The solar cell of the present embodiment includes at least one of the solar cell elements of the present embodiment, and is configured by disposing a wiring material on the electrode of the solar cell element. That is, the solar cell of the present embodiment includes the solar cell element and a wiring material disposed on the electrode of the solar cell element. The solar cell of the present embodiment is further configured by connecting a plurality of solar cell elements via a wiring material as needed, and further sealing them with a sealing material. The wiring material and the sealing material are not particularly limited and may be appropriately selected from those generally used in the technical field. [Examples]

Hereinafter, the invention will be specifically described by way of examples, but the invention is not limited to the examples. In addition, "%" is a quality standard unless otherwise specified.

<Example 1> (Preparation of composition 1 for passivation layer formation) 6.074 g of pentaethoxy ruthenium (Beixing Chemical Industry Co., Ltd., structural formula: Nb(OC ₂ H ₅ ) ₅ , molecular weight: 318.2), 5.930 g terpineol (Nippon Terpene Chemical Co., Ltd., sometimes abbreviated as "TPO"), and 16.800 g of isobornylcyclohexanol (Nippon Terpene Chemical Co., Ltd., sometimes abbreviated as "Terso" After mixing for 5 minutes, the mixture was mixed with 1.412 g of pure water and further kneaded for 5 minutes to prepare a composition 1 for passivation layer formation.

(Evaluation of thixotropy) A cone plate (50 mm in diameter and 1° cone angle) was mounted on a rotary shear viscometer (Antonpa, MCR301) at a temperature of 25 ° C and a shear rate of The shear viscosity of the prepared passivation layer-forming composition 1 was measured under the conditions of 0.1 s ^-1 and 10.0 s ^-1 , respectively. The shear viscosity (η ₁ ) at a shear rate of 0.1 s ^-1 was 47,400 Pa·s, and the shear viscosity (η ₂ ) at a shear rate of 10.0 s ^-1 was 4,250 Pa·s. The thixotropic ratio (η ₁ /η ₂ ) in the case where the shear rate was 0.1 s ^-1 and 10.0 s ^-1 was 11.2.

(Evaluation of Pattern Formability) When evaluating the pattern formation property of the composition for forming a passivation layer, a single-crystal p-type germanium substrate having a mirror surface shape (50 mm square, thickness 770 μm, hereinafter referred to as "矽" is used. The substrate ") is used as a semiconductor substrate.

In the evaluation of the pattern formation property, the prepared passivation layer-forming composition 1 was printed on the entire surface of the tantalum substrate by a screen printing method in the pattern shown in FIG. 8 on the entire surface other than the dot-shaped opening. Here, the pattern preparation point diameter (L _a ) of the dot-shaped opening portion used in the evaluation was 714 μm, the dot interval (L _b ) was 2.0 mm, the dot diameter (L _a ) was 535 μm, and the dot interval (L _{b )} It is 1.5 mm, the dot diameter (L _a ) is 357 μm, the dot interval (L _b ) is 1.0 mm, the dot diameter (L _a ) is 178 μm, and the dot interval (L _b ) is 0.5 mm. Thereafter, the tantalum substrate to which the composition 1 for passivation layer formation was applied was heated at 150 ° C for 5 minutes to transpire the liquid medium to perform a drying treatment. Then, the tantalum substrate was heat-treated (calcined) at a temperature of 700 ° C for 10 minutes, and then left to cool at room temperature (25 ° C). The heat treatment (calcination) was carried out under the conditions of an atmospheric atmosphere, a maximum temperature of 700 ° C, and a holding time of 10 minutes using a diffusion furnace (ACCURON CQ-1200, Hitachi International Electric Co., Ltd.).

To evaluate the formation of a pattern, the measurement point diameter (L _a) dot-shaped opening in the passivation layer on the substrate after the heat treatment (firing) the formed additional measurement point diameter of 10 points (L _a), is calculated which average value. Here, the spot diameter (L _a ) after printing is evaluated as A when the rate of change of the spot diameter (L _a ) after heat treatment (calcination) is less than 15%, and is evaluated as 15% or more and less than 30%. B, 30% or more are evaluated as C. When the evaluation is A or B, the patterning property of the composition for forming a passivation layer is good.

(Measurement of Effective Life) The prepared composition 1 for forming a passivation layer was printed on the entire surface of the ruthenium substrate by a screen printing method. Thereafter, the tantalum substrate to which the composition 1 for passivation layer formation was applied was heated at 150 ° C for 5 minutes, and the liquid medium was transpiration and dried. Thereafter, printing and drying treatment are also performed on the other surface of the ruthenium substrate. Then, the tantalum substrate was heat-treated (calcined) at a temperature of 700 ° C for 10 minutes, and then left to cool at room temperature (25 ° C). The heat treatment (calcination) was carried out under the conditions of an atmospheric atmosphere, a maximum temperature of 700 ° C, and a holding time of 10 minutes using a diffusion furnace (ACCURON CQ-1200, Hitachi International Electric Co., Ltd.).

The service life measuring device (Sumi Leber Co., Ltd., WT-2000 PVN, Japan) measured the effective life of the evaluation substrate obtained as described above by microwave reflection photoconduction attenuation method at room temperature (25 ° C). In the obtained evaluation substrate, the effective life of the region to which the composition for forming a passivation layer was applied was 325 μs.

(Production of Solar Cell Element) First, a single crystal p-type semiconductor substrate (125 mm square, thickness: 200 μm) was prepared, and a texture structure was formed on the light receiving surface and the back surface by alkaline etching. Next, in a mixed gas atmosphere of phosphorus chlorochloride (POCl ₃ ), nitrogen, and oxygen, the mixture was treated at a temperature of 900 ° C for 20 minutes to form an n ⁺ -type diffusion layer on the light-receiving surface, the back surface, and the side surface. Thereafter, side etching is performed to remove the PSG layer and the n ⁺ -type diffusion layer on the side surface, and then the PSG layer on the light-receiving surface and the back surface is removed using an etching solution containing hydrofluoric acid. Further, an etching treatment was additionally performed on the back surface to remove the n ⁺ -type diffusion layer on the back surface. Thereafter, an anti-reflection film containing tantalum nitride having a thickness of about 90 nm was formed by PECVD on the n ⁺ -type diffusion layer of the light-receiving surface.

Then, the prepared passivation layer-forming composition 1 was applied to the back surface in the pattern of FIGS. 5, 7, and 8, and then dried at 150 ° C for 5 minutes to use a diffusion furnace (Akuron). (ACCURON) CQ-1200, Hitachi International Electric Co., Ltd., heat treatment (calcination) under the conditions of an atmospheric environment, a maximum temperature of 700 ° C, and a holding time of 10 minutes to form a passivation layer 1. Further, in FIGS. 5, 7, and 8, in the subsequent step, the portion on which the back surface output extraction electrode is formed is removed, and the passivation layer 1 on the back surface is formed by exposing the p-type semiconductor substrate to a dot pattern. The pattern of the dot-shaped opening portion was the same as the smallest pattern among the users in the evaluation of the pattern formation property, and the dot diameter (L _a ) was 178 μm and the dot interval (L _b ) was 0.5 mm.

Then, on the light-receiving surface, a commercially available silver electrode paste (PV-16A, DuPont Co., Ltd.) was printed by the screen printing method in the pattern shown in FIG. The electrode pattern includes a 120 μm-wide light-receiving surface current collecting electrode and a 1.5 mm-wide light-receiving surface output extraction electrode, and the thickness is 20 μm after heat treatment (calcination), and the printing conditions are appropriately adjusted (mesh of the screen plate) , printing speed and printing pressure). This was heated at a temperature of 150 ° C for 5 minutes to transpire the liquid medium to carry out a drying treatment.

On the other hand, on the back side, a commercially available aluminum electrode paste (PVG-AD-02, PVG Solutions, Inc.) and a commercially available silver electrode paste (PV-505) were printed by the screen printing method in the pattern of FIG. DuPont Co., Ltd.). A pattern of the back surface output extraction electrode including the silver electrode paste was formed at 123 mm × 4 mm.

In addition, the printing conditions of the silver electrode paste and the aluminum electrode paste are appropriately adjusted so that the thickness of the back surface output extraction electrode and the back surface current collection electrode after heat treatment (calcination) is 20 μm (mesh of the screen plate, printing speed, and printing) Pressure). After each electrode paste was printed, it was heated at 150 ° C for 5 minutes, and the liquid medium was transpiration and dried.

Then, heat treatment (calcination) was carried out under the conditions of an atmospheric environment, a maximum temperature of 800 ° C, and a holding time of 10 seconds using a tunnel furnace (1 line of W/B tunnel furnace, Zebu Co., Ltd.). Solar cell element 1 of the desired electrode.

A wiring member (a rectangular wire for soldering a solar cell, a product name: SSA-TPS 0.2×1.5 (20), and a thickness of 0.2 mm) is disposed on the light-receiving surface output extraction electrode and the back surface extraction extraction electrode of the obtained solar cell element 1. × Copper wire with a width of 1.5 mm, coated with Sn-Ag-Cu lead-free solder for a thickness of up to 20 μm per side, Hitachi Metals Co., Ltd., using Tape Automated Bonding (TAB) The wire connecting device (NTS-150-M, Tabbing & Stringing Machine, NPC Co., Ltd.) melts the solder under the conditions of a maximum temperature of 250 ° C and a holding time of 10 seconds, thereby causing the wiring member and the light receiving unit The surface output extraction electrode and the back surface output extraction electrode are connected.

(Production of solar cell) Thereafter, a glass plate (whiteboard tempered glass 3KWE33, Asahi Glass Co., Ltd.), a sealing material (ethylene-vinyl acetate; EVA), and a back sheet were used, as shown in Fig. 10, to connect the sun. The battery element 12/sealing material 14/back sheet 15 is sequentially laminated to form a glass plate 16/sealing material 14/wiring material 13, and a vacuum laminator (LM-50×50, NPC Co., Ltd.) is used to expose a part of the wiring member In the manner, the laminate was vacuum laminated at a temperature of 140 ° C for 5 minutes to prepare a solar cell 1.

The solar cell's power generation performance can be evaluated by simulating sunlight (WXS-155S-10, Wing (WACOM) Co., Ltd.) and voltage-current (IV) evaluation tester (IV CURVE TRACER MP- 180. The measuring device of Yinghong Seiki Co., Ltd.) was combined. Jsc (short circuit current), Voc (open circuit voltage), FF (fill factor), and η (conversion efficiency) which are power generation performance of solar cells are respectively based on JIS-C-8913 (2005) and JIS-C-8914 (2005). Annual) obtained by measurement. The measured value obtained was converted into a relative value of a solar cell (solar battery R1) produced in Reference Example 1 to be described later as a relative value of 100.0.

<Example 2> In Example 1, ethyl acetate ethyl diisopropylaluminate (Kawasaki Seiki Co., Ltd., trade name: ALCH) was added to the composition for forming a passivation layer. Specifically, the content of each component was changed to pentaethoxy hydrazine (Beixing Chemical Industry Co., Ltd., structural formula: Nb(OC ₂ H ₅ ) ₅ , molecular weight: 318.2) of 2.997 g, and terpineol was 5.910 g. A passivation layer-forming composition 2 was prepared in the same manner as in Example 1 except that the isobornylcyclohexanol was 16.700 g, the ethyl acetate ethyl diisopropylate was 3.010 g, and the pure water was 1.404 g. . Then, in the same manner as in Example 1, the evaluation of the thixotropy of the composition for forming the passivation layer 2, the evaluation of the pattern formation property, and the evaluation of the effective life were performed. Further, in the same manner as in Example 1, the solar cell element 2 and the solar cell 2 were produced, and the power generation performance was evaluated.

<Example 3> In Example 1, a second squirrel aluminum (aluminum sec-butoxide) (Kawasaki Seiki Co., Ltd., trade name: ASBD) was added to the composition for forming a passivation layer. Specifically, the content of each component was changed to pentaethoxy hydrazine (Beixing Chemical Industry Co., Ltd., structural formula: Nb(OC ₂ H ₅ ) ₅ , molecular weight: 318.2) to 3.181 g, and terpineol was 6.004 g. A passivation layer-forming composition 3 was prepared in the same manner as in Example 1 except that the isobornylcyclohexanol was 16.822 g, the second butoxide-aluminum was 3.214 g, and the pure water was 1.447 g. Then, in the same manner as in Example 1, evaluation of thixotropy of the composition for forming passivation layer 3, evaluation of pattern formation property, and evaluation of effective life were performed. Further, in the same manner as in the first embodiment, the solar cell element 3 and the solar cell 3 were produced, and the power generation performance was evaluated.

<Example 4> In Example 1, the blending amount was changed. Specifically, the content of each component was changed to pentaethoxy hydrazine (Beixing Chemical Industry Co., Ltd., structural formula: Nb(OC ₂ H ₅ ) ₅ , molecular weight: 318.2) to 5.986 g, and terpineol was 5.889 g. A passivation layer-forming composition 4 was prepared in the same manner as in Example 1 except that the isobornylcyclohexanol was 16.638 g and the pure water was 0.999 g. Then, in the same manner as in Example 1, evaluation of thixotropy of the composition for forming passivation layer 4, evaluation of pattern formation property, and evaluation of effective life were performed. Further, in the same manner as in the first embodiment, the solar cell element 4 and the solar cell 4 were produced, and the power generation performance was evaluated.

<Example 5> In Example 2, the blending amount was changed. Specifically, the content of each component was changed to pentaethoxy hydrazine (Beixing Chemical Industry Co., Ltd., structural formula: Nb(OC ₂ H ₅ ) ₅ , molecular weight: 318.2) to 3.057 g, and terpineol was 6.272 g. A passivation layer-forming composition 5 was prepared in the same manner as in Example 1 except that the isobornylcyclohexanol was 17.740 g, the ethyl acetate ethyl diisopropylate aluminum was 3.121 g, and the pure water was 1.072 g. . Then, evaluation of thixotropy, evaluation of pattern formation property, and evaluation of effective life of the composition 5 for passivation layer formation were performed similarly to Example 1. Further, in the same manner as in the first embodiment, the solar cell element 5 and the solar cell 5 were produced, and the power generation performance was evaluated.

<Example 6> In Example 3, the blending amount was changed. Specifically, the content of each component was changed to pentaethoxy ruthenium (Beixing Chemical Industry Co., Ltd., structural formula: Nb(OC ₂ H ₅ ) ₅ , molecular weight: 318.2) 2.816 g, terpineol 5.763 g, and different A passivation layer-forming composition 6 was prepared in the same manner as in Example 1 except that 16.239 g of borneol-based cyclohexanol, 2.795 g of second butoxide aluminum, and 0.956 g of pure water were used. Then, in the same manner as in Example 1, evaluation of thixotropy of the composition for forming passivation layer 6, evaluation of pattern formation property, and evaluation of effective life were performed. Further, in the same manner as in the first embodiment, the solar cell element 6 and the solar cell 6 were produced, and the power generation performance was evaluated.

<Reference Example 1> In the preparation of the composition for forming a passivation layer of Example 2, pure water was not used. Specifically, the content of each component was changed to pentaethoxy hydrazine (Beixing Chemical Industry Co., Ltd., structural formula: Nb(OC ₂ H ₅ ) ₅ , molecular weight: 318.2) to be 2.928 g, and terpineol was 6.489 g. A passivation layer-forming composition R1 was prepared in the same manner as in Example 1 except that the isobornylcyclohexanol was 17.535 g and the ethyl acetate ethyl diisopropylate was 2.950 g. Then, in the same manner as in Example 1, evaluation of thixotropy of the passivation layer-forming composition R1, evaluation of pattern formation property, and evaluation of effective life were performed. Further, in the same manner as in the first embodiment, the solar battery element R1 and the solar battery R1 were produced, and the power generation performance was evaluated.

<Reference Example 2> In the preparation of the composition for forming a passivation layer of Example 2, the compound represented by the formula (I) was not used. Specifically, the content of each component was changed to 6.419 g of terpineol, 17.217 g of isobornylcyclohexanol, 3.268 g of ethyl acetoacetate diisopropoxide, and 1.495 g of pure water. The passivation layer-forming composition R2 was prepared in the same manner as in Example 1. Then, in the same manner as in Example 1, evaluation of thixotropy of the passivation layer-forming composition R2, evaluation of pattern formation property, and evaluation of effective life were performed. Further, in the same manner as in the first embodiment, the solar battery element R2 and the solar battery R2 were produced, and the power generation performance was evaluated.

<Comparative Example 1> In the preparation of the composition for forming a passivation layer of Example 1, the compound represented by the formula (I) was not used. Specifically, a passivation layer was formed in the same manner as in Example 1 except that the content of each component was changed to 6.015 g of terpineol, 16.815 g of isobornylcyclohexanol, and 1.423 g of pure water. Composition C1. Then, in the same manner as in Example 1, evaluation of thixotropy of the passivation layer-forming composition C1, evaluation of pattern formation property, and evaluation of effective life were performed. Further, in the same manner as in the first embodiment, the solar cell element C1 and the solar cell C1 were produced, and the power generation performance was evaluated.

The composition of each of the compositions for forming a passivation layer is shown in Table 1.

[Table 1]

[Table 2]

The thixotropic ratio, pattern formability, effective life, and power generation performance of the solar cell of the composition for forming a passivation layer which were carried out in Examples 1 to 6, Reference Examples 1 to 2, and Comparative Example 1 The evaluation results are shown in Table 2. The composition for forming a passivation layer prepared in Examples 1 to 6 was found to have good thixotropic ratio and pattern formability.

Further, the effective lifes evaluated in Examples 1 to 6 were considerably higher than the effective life measured in Comparative Example 1, and it was found that an excellent passivation layer derived from the compound of the formula (I) was formed.

When a composition containing the compound of the formula (I) or water is used as the composition for forming a passivation layer, the power generation performance of the produced solar cell tends to be relatively high. The reason for this is that the compound of the formula (I) and water are contained in the composition for forming a passivation layer as described above, and the pattern formation property is improved, and the dot diameter (L _a ) of the pattern of the passivation layer is determined when the solar cell is produced. The area ratio of the contact between the aluminum electrode paste and the semiconductor substrate is ensured.

In addition, when a composition containing both the compound of the formula (I) and the organoaluminum compound is used as the composition for forming a passivation layer, the power generation performance of the produced solar cell tends to be relatively high. With regard to this phenomenon, it is considered that both the compound of the formula (I) and the organoaluminum compound are contained in the composition for forming a passivation layer, and thus a composite oxide of a metal derived from the compound of the formula (I) and aluminum is formed by heat treatment (calcination). A more dense passivation layer having a large negative fixed charge is formed, and the passivation effect is further improved.

Further, according to the results of the third embodiment and the sixth embodiment, when the compound of the formula (I) is contained in the composition for forming a passivation layer, the passivation effect is also high, which contributes to an improvement in power generation performance of the solar cell.

It is understood that the solar cell produced in Reference Example 1 and Reference Example 2 has lower power generation performance than Examples 1 to 6. With regard to this phenomenon, it is considered that the viscosity and the thixotropic ratio of the compositions for forming the passivation layer R1 and R2 are low, and the dot diameter (L _a ) of the pattern of the passivation layer in the preparation of the solar cell cannot be maintained, and the aluminum electrode paste and the semiconductor substrate are not. The contact area ratio between the two is lowered.

The power generation performance of the solar cell produced in Comparative Example 1 was lower than that of Reference Example 1 and Reference Example 2 and Examples 1 to 6. In this case, it is considered that the compound of the formula (I) is not contained in the composition for forming the passivation layer C1, and a film which is produced by heat treatment (calcination) of the compositions is not sufficiently punctured. In addition, the disclosure of Japanese Patent Application No. 2014-138951, filed on Jul. 4, 2014, is hereby incorporated by reference. In addition, all the documents, patent applications, and technical specifications described in the present specification are incorporated by reference to the extent that they are specifically and separately incorporated by reference to the respective documents, patent applications, and technical specifications. To this manual.

1‧‧‧p-type semiconductor substrate
2‧‧‧n ⁺ type diffusion layer
3‧‧‧PSG layer
4‧‧‧Anti-reflective film
5‧‧‧ Passivation layer
6, 11‧‧‧ aluminum electrodes for collecting electricity on the back
7‧‧‧Back output take-out electrode
8‧‧‧Accepting the surface of the light collecting electrode
9‧‧‧Lighted surface output extraction electrode
10‧‧‧p ⁺ diffusion layer
12‧‧‧Solar battery components
13‧‧‧Wiring materials
14‧‧‧ Sealing material
15‧‧‧After
16‧‧‧ glass plate
L _a ‧‧‧ point diameter
L _b ‧‧‧ point interval
A‧‧‧ part of the pattern formed on the back side of the passivation layer
B‧‧‧ Part of the pattern formed on the back side of the passivation layer

1(1) to 1(9) are cross-sectional views schematically showing an example of a method of manufacturing a solar cell element including the passivation layer of the present embodiment. 2(10) to 2(18) are cross-sectional views schematically showing another example of a method of manufacturing a solar cell element including the passivation layer of the present embodiment. 3(19) to 3(29) are cross-sectional views schematically showing another example of a method of manufacturing a solar cell element including the passivation layer of the present embodiment. 4 is a schematic plan view showing an example of a light receiving surface of the solar battery element of the embodiment. FIG. 5 is a schematic plan view showing an example of a formation pattern of the back surface of the passivation layer of the embodiment. FIG. 6 is a schematic plan view showing another example of the formation pattern of the back surface of the passivation layer of the embodiment. Fig. 7 is a schematic plan view showing an enlarged portion A of Fig. 5; Fig. 8 is a schematic plan view showing an enlarged portion B of Fig. 5; FIG. 9 is a schematic plan view showing an example of a back surface of the solar battery element of the embodiment. FIG. 10 is a view for explaining an example of a method of manufacturing a solar cell according to the embodiment.

1‧‧‧p-type semiconductor substrate

2‧‧‧n ⁺ type diffusion layer

3‧‧‧PSG layer

4‧‧‧Anti-reflective film

5‧‧‧ Passivation layer

6‧‧‧Aluminum electrode for back collector

7‧‧‧Back output take-out electrode

8‧‧‧Accepting the surface of the light collecting electrode

9‧‧‧Lighted surface output extraction electrode

10‧‧‧p ⁺ diffusion layer

Claims (12)

A composition for forming a passivation layer comprising a compound represented by the following formula (I), water; M(OR ¹ ) _m (I) [In the formula (I), M represents a group selected from Al, Nb, Ta And at least one of the group consisting of VO, Y, and Hf; R ¹ each independently represents an alkyl group or an aryl group; and m represents an integer of 1 to 5]. A composition for forming a passivation layer comprising a hydrolyzate of a compound represented by the following formula (I); M(OR ¹ ) _m (I) [In the formula (I), M represents a group selected from the group consisting of Al, Nb, At least one of the group consisting of Ta, VO, Y, and Hf; R ¹ each independently represents an alkyl group or an aryl group; m represents an integer of 1 to 5]. The composition for forming a passivation layer according to claim 1 or 2, further comprising a compound represented by the following formula (II); [In the formula (II), R ² each independently represents an alkyl group; n represents an integer of 1 to 3; and X ² and X ³ each independently represent an oxygen atom or a methylene group; and R ³ , R ⁴ and R ⁵ respectively Independently represents a hydrogen atom or an alkyl group]. The composition for forming a passivation layer according to any one of the items 1 to 3, wherein M in the compound represented by the formula (I) is Nb. The composition for forming a passivation layer according to any one of claims 1 to 4, wherein the mass M1 in the case of heating at 150 ° C for 3 hours is divided by the mass without heating The ratio (M1/M2) calculated by M2 is 0.0001 to 0.7. The composition for forming a passivation layer according to any one of claims 1 to 4, wherein a shearing viscosity η1 at a shear rate of 25 ° C of 0.1 s ^-1 is divided by a shear rate of 10.0. The thixotropic ratio (η1/η2) calculated by the shear viscosity η2 of s ^-1 is 1.05 to 100. The composition for forming a passivation layer according to any one of claims 1 to 4, wherein the mass M1 in the case of heating at 150 ° C for 3 hours is divided by the mass without heating The ratio (M1/M2) calculated by M2 is 0.0001 to 0.7, and the shear viscosity η1 at a shear rate of 25 ° C of 0.1 s ^-1 is divided by the shear viscosity η 2 of a shear rate of 10.0 s ^-1 . The transformation ratio (η1/η2) is 1.05 to 100. A semiconductor substrate with a passivation layer, comprising: a semiconductor substrate; a passivation layer provided on at least a portion of at least one surface of the semiconductor substrate, as in any one of claims 1 to 7 The heat-treated product of the composition for forming a passivation layer. A method of producing a semiconductor substrate with a passivation layer, comprising: providing a composition for forming a passivation layer according to any one of items 1 to 7 of the invention, at least a part of at least one surface of the semiconductor substrate And forming a composition layer; and heat-treating the composition layer to form a passivation layer. A solar cell element comprising: a semiconductor substrate including a pn junction portion in which a p-type layer and an n-type layer are pn-bonded; and a passivation layer provided on at least a portion of at least one surface of the semiconductor substrate The heat-treated product of the composition for forming a passivation layer according to any one of claims 1 to 7, wherein the electrode is disposed on at least one of the p-type layer and the n-type layer. A method for producing a solar cell element, comprising: at least a part of at least one surface of a semiconductor substrate including a pn junction portion in which a p-type layer and an n-type layer are pn-bonded is given in the first to the first a step of forming a composition layer by using a composition for forming a passivation layer according to any one of items 7; a step of heat-treating the composition layer to form a passivation layer; and at least a p-type layer and an n-type layer The step of arranging the electrodes on one of the layers. A solar cell comprising: the solar cell element according to claim 10; and a wiring material disposed on the electrode of the solar cell element.