TW201808976A - Composition for forming a passivation layer, semiconductor substrate with passivation layer, method for producing semiconductor substrate with passivation layer, method for producing solar cell element, solar cell element, and solar cell - Google Patents

Abstract

A composition for forming a passivation layer includes a compound represented by the following formula (I). Bi (OR1)m(I) Each R1 independently represents an alkyl group, an aryl group or an acyl group, and m represents 3 or 5.

Description

Composition for forming a passivation layer, semiconductor substrate with passivation layer, method for producing semiconductor substrate with passivation layer, method for producing solar cell element, solar cell element, 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 a semiconductor substrate with a passivation layer, a solar cell element, a method for producing a solar cell element, and a solar cell.

An example of a manufacturing procedure of a 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, and then subjected to a mixed gas atmosphere of phosphorus, chlorine (POCl ₃ ), nitrogen, and oxygen at 800 ° C to 900 ° C. The n-type diffusion layer is uniformly formed on the surface of the p-type germanium substrate by tens of minutes of processing.

In this conventional method, since phosphorus is diffused by using a mixed gas, an n-type diffusion layer is formed not only on the light-receiving 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 is performed. Further, it is necessary to convert the n-type diffusion layer formed on the back surface into a p ⁺ -type diffusion layer. Therefore, an aluminum paste containing aluminum powder and a binder is applied to the entire back surface or a part thereof, and heat-treated (calcined), whereby the n-type diffusion layer is converted into a p ⁺ -type diffusion layer, and obtained by forming an aluminum electrode. Ohmic contact.

However, the aluminum electrode formed of the aluminum paste has a low electrical conductivity. Therefore, in order to lower the sheet resistance of the aluminum electrode, the aluminum electrode which is usually formed on the entire back surface needs to have a thickness of about 10 μm to 20 μm after heat treatment (calcination). Further, since the thermal expansion coefficient of bismuth and aluminum is greatly different, a large internal stress is generated in the ruthenium substrate during the heat treatment (calcination) and cooling for forming the aluminum electrode on the ruthenium substrate. This large internal stress is a cause of damage to the grain boundary, growth of crystal defects, and 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 aluminum electrode 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 there is a problem that the characteristics of the solar cell are lowered. Happening.

In connection with the above, it has been proposed to partially contact the point where the p ⁺ -type diffusion layer is in contact with the aluminum electrode by applying an aluminum paste to a part of the opposite surface (hereinafter also referred to as "back surface") of the light-receiving surface of the substrate (for example, refer to Patent Document 1). In the case of a solar cell having a point contact structure on the back surface, it is necessary to suppress the recombination speed of a minority carrier in the surface of the ruthenium substrate on which the aluminum electrode is not formed. As the passivation layer for the back surface to solve the problem, an SiO ₂ film or the like has been proposed (for example, refer to Patent Document 2). By terminating the dangling bonds of the ruthenium atoms in the surface layer portion of the back surface of the ruthenium substrate, the surface level density which is a cause of recombination is reduced, and the passivation effect by providing such an SiO ₂ film is exhibited.

Further, 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 an alumina (Al ₂ O ₃ ) film or the like is proposed as a material having a negative fixed charge (for example, refer to Patent Document 3). Such a passivation layer is generally formed by a method such as an atomic layer deposition (ALD) method or a chemical vapor deposition (CVD) method (for example, see Non-Patent Document 1). [Prior Art Document] [Patent Literature]

[Patent Document 1] Japanese Patent No. 3107287 [Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-6565 [Patent Document 3] Japanese Patent No. 4767110 [Non-Patent Document]

[Non-Patent Document 1] Journal of Applied Physics, 104 (2008), 113703-1 to 113703-7

[Problems to be Solved by the Invention] However, the technique described in Non-Patent Document 1 includes complicated manufacturing steps such as vapor deposition, and thus it is difficult to improve productivity.

Therefore, as a simple method of forming a passivation layer on a semiconductor substrate, the inventors have studied a composition for forming a passivation layer containing a specific metal compound. In the method of using a composition for forming a passivation layer, a passivation layer can be formed on a semiconductor substrate by a simple method such as a printing method.

Here, as a composition for forming a passivation layer, a passivation layer capable of suppressing generation of cracks and cracks and having excellent passivation effect can be formed by a simple method.

In view of the above-mentioned facts, an object of the present invention is to provide a composition for forming a passivation layer which can form a passivation layer having a good film quality and excellent passivation effect by a simple method. Further, an object of one aspect of the present invention is to provide a semiconductor substrate with a passivation layer, a solar cell element, and a solar cell including a passivation layer having a good film quality and excellent passivation effect. Moreover, an object of one aspect of the present invention is to provide a method for producing a semiconductor substrate with a passivation layer capable of forming a passivation layer having excellent passivation effect by a simple method, and a method for producing a solar cell element. [Means for solving the problem]

The specific means for achieving the above problems are as follows. <1> A composition for forming a passivation layer, which comprises a compound represented by the following formula (I); Bi(OR ¹ ) _m (I) [R ¹ each independently represents an alkyl group, an aryl group or a fluorenyl group; m represents 3 or 5]. <2> The composition for forming a passivation layer according to <1>, which further comprises water. <3> The composition for forming a passivation layer according to <1>, which comprises a hydrolyzate of the compound represented by the above formula (I). The composition for forming a passivation layer according to any one of <1> to <3> which further comprises a compound represented by the following formula (III); M(OR ⁶ ) _l (III) [ In the formula (III), M represents at least one selected from the group consisting of Nb, Ta, VO, Y and Hf; R ⁶ each independently represents an alkyl group, an aryl group or a fluorenyl group; and 1 represents a valence of M ]. <5> The composition for forming a passivation layer according to <4>, wherein M in the compound represented by the formula (III) is Nb. <6> The composition for forming a passivation layer according to <4>, which comprises a hydrolyzate of the compound represented by the above formula (III). <7> A semiconductor substrate with a passivation layer, comprising: a semiconductor substrate; and a passivation layer which is any one of <1> to <6> provided on at least a part of at least one surface of the semiconductor substrate The heat treatment of the composition for forming a passivation layer. (8) 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 <6>, wherein at least one of the surfaces of at least one of the semiconductor substrates is provided And forming a composition layer; and subjecting the composition layer to heat treatment to form a passivation layer. <9> 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 <6>, wherein the electrode is disposed on at least one of the p-type layer and the n-type layer. <10> 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; and the p-type layer and the n-type The step of arranging electrodes on at least one of the layers. <11> The method for producing a solar cell element according to the above aspect, wherein the step of forming a composition for forming a passivation layer to form a composition includes a screen printing method. <12> A solar cell comprising: the solar cell element according to <9>; and a wiring material disposed on the electrode of the solar cell element. [Effects of the Invention]

According to one aspect of the present invention, it is possible to provide a composition for forming a passivation layer which can form a passivation layer having a good film quality and excellent passivation effect by a simple method. Moreover, according to one aspect of the present invention, a semiconductor substrate with a passivation layer, a solar cell element, and a solar cell including a passivation layer having a good film quality and a passivation effect can be provided. Moreover, according to one aspect of the present invention, a method for producing a semiconductor substrate with a passivation layer capable of forming a passivation layer having excellent passivation effect by a simple method, and a method for producing a solar cell element can be provided.

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, the constituent elements (including the element steps and the like) are not essential except for the case where they are specifically indicated, the case where it is obviously necessary in principle, and the like. 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 numerical ranges recited in the present specification, the upper limit or the lower limit described in one numerical range may be replaced with the upper or lower limit of the numerical range described in the other step. Further, in the numerical ranges described in the specification, the upper or lower limit of the numerical range is replaced with the value shown in the examples. In the present specification, when the content or content of each component in the composition is such that a plurality of substances corresponding to the respective components are present in the composition, unless otherwise specified, the various substances present in the composition are indicated. Total content or content. In the present specification, the term "layer" is used as a plan view, and includes a configuration formed in a part of a shape other than the shape formed on the entire surface. Further, in the present specification, the "layer" may be referred to as "film".

The "passivation layer" in the present embodiment refers to a layer having an effect of suppressing recombination of carriers generated in a semiconductor (hereinafter sometimes referred to as a passivation effect). A specific method for suppressing recombination of carriers generated in a semiconductor may be exemplified by terminating a semiconductor surface defect (dangling bond) by forming a passivation layer, and enabling the passivation layer to have a fixed charge. Method such as band bending. Moreover, the passivation layer may have the effect other than those as needed. Specifically, effects such as protecting the surface of the semiconductor and functioning as an antireflection film by having a desired refractive index are exemplified.

In the present specification, the term "membrane" refers to a quality in which a film is in an appropriate state in order to exhibit a passivation effect. In the case where the film quality is good, the passivation effect of the film is not impaired, and the in-plane uniformity is excellent. Further, it is preferable that the film having a good film quality is excellent in uniformity of film thickness, and the film density and refractive index are excellent in uniformity in the in-plane and thickness directions, and suppress cracking, cracking, or peeling. The film quality can be easily evaluated by an observation method generally used. For example, when the surface is observed using an optical microscope, a film having no crack, crack or peeling, or a film having relatively few cracks, cracks, or peeling can be evaluated as having a good film quality. Further, the evaluation can be carried out in detail by a physical property evaluation method of a film which is generally used. For example, using an automatic ellipsometer, the film thickness and the refractive index are measured at several points in the plane by a usual method, and the smaller the standard deviation of the values of the film thickness and the refractive index, the better the film quality can be evaluated.

<Composition for Forming Passivation Layer> The composition for forming a 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)").

_{^{Bi (OR 1) m (I}} )

In the formula (I), R ¹ each independently represents an alkyl group, an aryl group or a fluorenyl group. m represents 3 or 5.

By including the compound of the formula (I) in the composition for forming a passivation layer, a passivation layer having a good film quality and excellent passivation effect can be formed by a simple method.

Further, since the composition for forming a passivation layer contains the compound of the formula (I), it is easy to maintain the passivation effect even after a process such as high temperature or vacuum after forming 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 Semilab Co., Ltd., and a few of the semiconductor substrates on which the passivation layer is formed are measured by a microwave reflection photoconductive attenuation method. The carrier was evaluated for its useful life.

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 main 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)

Furthermore, the effective life is longer, indicating that the recombination speed of a few carriers is slow. Further, by forming a solar cell element using a semiconductor substrate having a long effective life, power generation performance tends to be improved.

(Compound represented by the formula (I)) The composition for forming a passivation layer of the present embodiment contains the compound represented by the formula (I) (the compound of the formula (I)). By including the compound of the formula (I) in the composition for forming a passivation layer, a passivation layer having an excellent passivation effect can be formed. The reason for this can be considered as follows. Further, the composition for forming a passivation layer may contain one compound of the formula (I), or may contain two or more kinds.

The ruthenium oxide (Bi ₂ O ₃ or Bi ₂ O ₅ ) formed by heat-treating (calcining) the composition for forming a passivation layer containing the compound of the formula (I) has a defect of a ruthenium atom or an oxygen atom, and is easily produced. Large negative fixed charge. The fixed charge can reduce the concentration of a minority carrier by generating an electric field 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, regarding the state of the passivation layer which generates a fixed charge on the semiconductor substrate, the cross section of the semiconductor substrate can be observed by a scanning transmission electron microscope (STEM, Scanning Transmission Electron Microscope), and the electron energy loss spectroscopy method can be used ( The analysis of EELS and Electron Energy Loss Spectroscopy was carried out to confirm the combination of patterns. 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 formula (I), R ¹ each independently represents an alkyl group, an aryl group or a fluorenyl group. m represents 3 or 5. Preferably, R ^{1 is} independently an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms or a fluorenyl group having 1 to 10 carbon atoms. The alkyl group represented by R ¹ may be linear or branched. The alkyl group and the aryl group represented by R ¹ each may have a substituent or may be unsubstituted, and are preferably unsubstituted. m is preferably 3. The substituent of the alkyl group may, for example, be an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group or the like. The substituent of the aryl group may, for example, be a methyl group, an ethyl group, an isopropyl group, an amine group, a hydroxyl group, a carboxyl group, a sulfo group or a nitro group. The fluorenyl group represented by R ¹ includes a carbonyl moiety and a hydrogen atom directly bonded to a carbon atom of the alkyl moiety, the aryl moiety or the carbonyl moiety. The alkyl moiety in the fluorenyl group represented by R ¹ may be linear or branched. The alkyl moiety and the aryl moiety in the fluorenyl group represented by R ¹ may have a substituent or may be unsubstituted, and are preferably unsubstituted. The substituent of the alkyl moiety in the fluorenyl group represented by R ¹ may, for example, be an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group, a phenyl group or the like, and the substituent of the aryl moiety in the fluorenyl group represented by R ¹ may be A methyl group, an ethyl group, an isopropyl group, an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group, etc. are mentioned. Further, the carbon number of the alkyl group, the aryl group and the fluorenyl group represented by R ¹ does not include the carbon number of the substituent. Specific examples of the alkyl group represented by R ¹ include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a second butyl group, a t-butyl group, a n-hexyl group, and an n-octyl group. , 2-ethylhexyl, 3-ethylhexyl, and the like. Specific examples of the aryl group represented by R ¹ include a phenyl group and the like. Specific examples of the mercapto group represented by R ¹ include a mercapto group, an ethenyl group, a benzamidine group, a 2-ethylhexyl group, and the like. Among them, R ^{1 is} preferably a fluorenyl group from the viewpoint of storage stability.

The state of the compound of formula (I) may be either solid or liquid at 25 °C. The compound of the formula (I) is preferred from the viewpoints of storage stability of the composition for forming a passivation layer and mixing with water, an alumina precursor or a compound represented by the formula (III) which are optionally contained. It is a liquid at 25 ° C.

Specific examples of the compound of the formula (I) include cerium (III) acetate, cerium trihexanoate, cerium tris(2-ethylhexanoate), cerium trioctanoate, cerium tris(2,2-dimethyloctanoic acid), and three Neodymium neodecanoate, isopropoxy oxime, and the like. Among them, the compound of the formula (I) is preferably tris(2-ethylhexanoate) ruthenium.

Further, the compound of the formula (I) may be a manufacturer or a commercially available product. Commercially available products include tris(2-ethylhexanoic acid) hydrazine manufactured by Azmax Co., Ltd., and the like.

The compound of the formula (I) can be prepared by reacting a halide of hydrazine 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 Publication No. SHO 63-227593 A known manufacturing method such as Japanese Patent Laid-Open No. Hei 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, which will be described later, and is contained in the composition for forming a passivation layer.

The presence of the alkoxide structure in the compound of formula (I) can be confirmed by the analytical methods 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 content of the compound of the formula (I) contained in the composition for forming a passivation layer can be appropriately selected as needed. From the viewpoint of the passivation effect, the content of the compound of the formula (I) is preferably from 1% by mass to 80% by mass, and more preferably from 3% by mass to 3% by mass based on the total mass of the composition for forming a passivation layer. 50% by mass, more preferably 5% by mass to 30% by mass, particularly preferably 7% by mass to 20% by mass.

When the composition for forming a passivation layer contains an alumina precursor to be described later, the content of the compound of the formula (I) is not particularly limited. In the case where the total content of the compound of the formula (I) and the alumina precursor is 100% by mass, the content of the compound of the formula (I) in the composition for forming a passivation layer is, for example, preferably 0.5% by mass to 90%. The mass % is more preferably 1% by mass to 75% by mass, still more preferably 2% by mass to 70% by mass, and particularly preferably 3% by mass to 70% by mass. When the content of the compound of the formula (I) is 0.5% by mass or more, the passivation effect tends to be improved. In addition, when the content of the compound of the formula (I) is 90% by mass or less, the storage stability of the composition for forming a passivation layer tends to be improved.

(Water) The composition for forming a passivation layer may also contain water. Further, the composition for forming a passivation layer may further comprise a hydrolyzate of the compound of the formula (I).

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 composition for forming a passivation layer preferably contains a compound of the formula (I) and water. The hydrolyzate of the compound of formula (I) is formed into a network by metal compounds by reacting water with a compound of formula (I) to form a hydrolyzate of the compound of formula (I). 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, when the shear rate of the composition for forming a passivation layer is high, the viscosity ratio when the shear rate is low, that is, the thixotropic ratio is improved, and the thixotropy required for pattern formation is exhibited.

The composition for forming a passivation layer further enhances the shape stability of the composition layer formed by imparting a composition for forming a passivation layer onto a semiconductor substrate by causing water to act on the compound of the formula (I). It becomes possible to selectively form a passivation layer in a desired shape at a desired position in a region where the composition layer is formed. Therefore, in the composition for forming a passivation layer containing water, at least one of the thixotropic agent and the resin to be described later is not required in order to exhibit desired thixotropy (hereinafter, at least one of the thixotropic agent and the 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 residual thermal decomposition product such as a thixotropic agent affects the characteristics of the passivation layer. Case. 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 substance, there is a case where the thixotropic agent does not scatter and remains in passivation even after a heat treatment (calcination) step. The phenomenon in the layer. There is a case where the residual thixotropic agent affects the characteristics of the passivation layer.

On the other hand, in the composition for forming a passivation layer containing water, 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.

As described above, by including water in the composition for forming a passivation layer, a passivation layer having excellent patterning property and excellent passivation effect can be formed by a simple method. Further, by using a composition for forming a passivation layer having excellent pattern formation properties, a passivation layer having a desired shape can be formed. 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 passivation layer can be appropriately selected as needed. The content of water is preferably 0.01% by mass or more, and more preferably 0.03% by mass, based on the total mass of the composition for forming a passivation layer, from the viewpoint of imparting thixotropy to the composition for forming a passivation layer. The above is more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more. In addition, the content of water is preferably 80% by mass or less, and more preferably 70% by mass or less, based on the total mass of the composition for forming a passivation layer, from the viewpoint of the pattern formation property and the passivation effect. Further preferably, it is 60% by mass or less, and particularly preferably 50% by mass or less.

The compound of the formula (I) in the composition for forming a passivation layer (in the case where the composition for forming a passivation layer contains an alumina precursor, a compound of the formula (III), a ruthenium compound or the like, the compound of the formula (I) and the like The amount of water that acts in total can be calculated from the amount of alcohol or carboxylic acid free from the compound of formula (I). When water is allowed to act on the compound of formula (I), an alcohol or carboxylic acid is freed from the compound of formula (I). The amount of the free alcohol or carboxylic acid 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 or carboxylic acid. The measurement of the amount of the free alcohol or carboxylic acid can be confirmed, for example, by gas chromatography mass spectrometry (GC-MS).

The content of the alcohol or the carboxylic acid contained in the composition for forming a passivation layer is, for example, 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.

Further, the passivation layer forming composition may contain at least one hydrolyzate of the compound of the formula (I), and may further contain at least one hydrolyzate of an alumina precursor described later, or may contain at least one compound of the formula (III) described later. A hydrolyzate. Further, in the hydrolyzate of the compound of the formula (I), a dehydrated condensate of the hydrolyzate of the compound of the formula (I) may be contained, and in the hydrolyzate of the alumina precursor, the hydrolyzate of the alumina precursor may be dehydrated. The condensate may, in the hydrolyzate of the compound of the formula (III), a dehydrated condensate of the hydrolyzate of the compound of the formula (III).

In the composition for forming a passivation layer containing water, the content of the compound of the formula (I) is the total content of the hydrolyzate of the compound of the formula (I) and the compound of the formula (I) in the composition for forming a passivation layer. In addition, the content of the alumina precursor to be described later in the composition for forming a passivation layer containing water is the total content of the alumina precursor of the passivation layer-forming composition and the hydrolyzate of the alumina precursor. Further, in the composition for forming a passivation layer containing water, the content of the compound of the formula (III) to be described later is the total content of the hydrolyzate of the compound of the formula (III) and the compound of the formula (III) in the composition for forming a passivation layer. . Further, in the composition for forming a passivation layer containing water, the content of the cerium compound is the total content of the cerium compound and the hydrolyzate of the cerium compound in the composition for forming a passivation layer.

(Alumina Precursor) The composition for forming a passivation layer may also contain an alumina precursor. The alumina precursor is not particularly limited as long as it is alumina formed by heat treatment (calcination). Further, the composition for forming a passivation layer may contain one type of alumina precursor, and may contain two or more types.

The alumina precursor is alumina (Al ₂ O ₃ ) by heat treatment (calcination). At this time, the formed alumina is likely to be in an amorphous state, and it is easy to form a 4-coordinate alumina layer in the vicinity of the interface with the semiconductor substrate. Due to the 4-coordinated aluminum oxide layer, a large negative fixed charge can be obtained in the vicinity of the interface with the semiconductor substrate. Thereby, an electric field is generated in the vicinity of the interface with the semiconductor substrate, and the concentration of the minority carrier can be lowered. As a result, the carrier recombination speed at the interface with the semiconductor substrate is suppressed, and an excellent passivation effect is obtained.

In addition to the above, by combining the compound of the formula (I) with an alumina precursor, the passivation effect is further increased in the passivation layer due to the respective effects. Further, by performing heat treatment (calcination) in a state in which the compound of the formula (I) is mixed with an alumina precursor, the composite metal alkoxide of bismuth (Bi) and aluminum (Al) contained in the compound of the formula (I) can be improved. The physical properties such as reactivity and 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 present specification, the density of the passivation layer can be evaluated by using a transmission electron microscope to visually recognize the difference in the contrast of the observed image and the presence or absence of voids.

The alumina precursor can be either liquid or solid. From the viewpoint of self-passivation effect and storage stability, in the case of using stability at normal temperature (for example, 25 ° C) and a liquid medium, it is desirable to use an alumina precursor having good solubility or dispersibility in a liquid medium. Things. By using such an alumina precursor, the homogeneity of the formed passivation layer is further improved, so that the desired passivation effect tends to be stably obtained.

As the alumina precursor, an organic alumina precursor is preferably used, and examples thereof include a compound represented by the following formula (II) (hereinafter also referred to as "specific aluminum compound").

In the formula (II), R ² each independently represents an alkyl group. n represents an integer of 0 to 3. X ² and X ³ each independently represent an oxygen atom or a methylene group. R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group. Here, when there are a plurality of R ² to R ⁵ , X ² and X ³ , the groups represented by the plurality of identical symbols may be the same or different.

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. The alkyl group represented by R ² may have a substituent or may be unsubstituted, and is preferably unsubstituted. The substituent of the alkyl group may, for example, be an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group or the like. Further, the carbon number of the alkyl group represented by R ² does not contain the carbon number of the substituent.

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 alkyl group having 1 to 4 carbon atoms. base.

Specific examples of the alkyl group represented by R ² include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a second butyl group, a tert-butyl group, a n-hexyl group, and an n-octyl group. , 2-ethylhexyl, 3-ethylhexyl, and the like.

In the formula (II), n represents an integer of 0 to 3. It is preferably an integer of 1 to 3, more preferably 1 or 3, from the viewpoint of suppressing occurrence of defects such as gelation and ensuring storage stability over time, and further preferably from the viewpoint of solubility. it's 1.

Further, X ² and X ³ in the formula (II) 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, preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or a carbon number. An alkyl group of 1 to 4. Alkyl R ^3, R ⁴ and R ⁵ may be represented may also be linear or branched. The alkyl group represented by R ³ , R ⁴ and R ⁵ may have a substituent or may be unsubstituted, and is preferably unsubstituted. The substituent of the alkyl group may, for example, be an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group or the like. Further, the carbon number of the alkyl group represented by R ³ , R ⁴ and R ⁵ does not contain the carbon number of the substituent.

Among them, R ³ and R ⁴ in the general formula (II) are preferably independently a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms, from the viewpoints of storage stability and passivation effect. Preferred are a hydrogen atom or an unsubstituted alkyl group having 1 to 4 carbon atoms. Further, R ⁵ in the general formula (II) is preferably 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.

Specific examples of the alkyl group represented by R ³ , R ⁴ and R ⁵ in the formula (II) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, an isobutyl group and a second butyl group. , tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, 3-ethylhexyl, and the like.

From the viewpoint of storage stability and passivation effect, the specific aluminum compound is preferably at least one selected from the group consisting of: n in the formula (II) is 0, and R ^{2 is} independently a carbon number of 1 a compound of an alkyl group of ～4; and n in the formula (II) is an integer of 1 to 3, and each of R ^{2 is} independently an alkyl group having 1 to 4 carbon atoms, and at least one of X ² and X ³ is oxygen. Each of R ³ and R ^{4 is} independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and each of R ^{5 is} independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. More preferably, the specific aluminum compound is at least one selected from the group consisting of: n in the formula (II) is 0, and R ^{2 is} independently an unsubstituted alkyl group having 1 to 4 carbon atoms; And n in the formula (II) is an integer of 1-3, 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 ⁴ to which the methylene group is bonded is hydrogen. A compound in which R ⁵ is a hydrogen atom.

From the viewpoint of the storage stability of the chelate formation, the specific aluminum compound is preferably a compound in which n is 1 to 3 in the formula (II), and R ^{5 is} independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. base.

Specific aluminum compounds (aluminum trialkoxide) in which n is 0 represented by the formula (II) include, for example, trimethoxy aluminum, triethoxy aluminum, triisopropoxy aluminum, and tri-butoxy group. Aluminum, single second butoxy-diisopropoxy aluminum, tri-tert-butoxy aluminum, tri-n-butoxy aluminum, and the like.

Further, specific examples of the specific aluminum compound in which n is an integer of 1 to 3 represented by the formula (II) include ethyl acetacetate aluminum diisopropylate, ethyl acetoacetate, aluminum diisopropylate, and the like. Ethyl acetate ethyl acetate) aluminum, bis(acetonitrile ethyl acetate) monoethylammonium acetone, tris(acetonitrile)aluminum, and the like.

Further, the specific aluminum compound in which n represented by the formula (II) is an integer of 1 to 3 may be a manufacturer or a commercially available product. Commercially available products include, for example, trade name ALCH, ALCH-50F, ALCH-75, ALCH-TR, ALCH-TR-20, Alumichelate M, and Alumichelate. D and Alumichelate A (W).

Further, the specific aluminum compound in which n is an integer of 1 to 3 represented by the formula (II) can be produced by mixing 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 aluminum trialkoxide is mixed with a compound having a specific structure of two carbonyl groups, at least a part of the alkoxy group of the aluminum trialkoxide is substituted with a compound having 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 an aluminum chelate structure, the stability of the specific aluminum 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, a compound having a specific structure of two carbonyl groups is preferably at least selected from the group consisting of a β-diketone compound, a β-ketoester compound, and a malonic acid diester. One. Specific examples of the compound having two specific structures of a carbonyl group include acetamidine acetone, 3-methyl-2,4-pentanedione, 2,3-pentanedione, and 3-ethyl-2,4-pentane. Ketone, 3-butyl-2,4-pentanedione, 2,2,6,6-tetramethyl-3,5-heptanedione, 2,6-dimethyl-3,5-heptanedione a β-diketone compound such as 6-methyl-2,4-heptanedione; methyl acetate acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, acetonitrile acetate Butyl ester, n-butyl acetate, n-butyl acetate, n-butyl acetate, n-amyl acetate, isoamyl acetate, n-hexyl acetate, n-octyl acetate, n-glycolic acid Ester, 3-pentyl acetate, ethyl 2-ethenyl heptanoate, ethyl 2-methylacetate, ethyl 2-butylacetate, ethyl hexylacetate, 4, Ethyl 4-dimethyl-3-oxoethoxyvalerate, ethyl 4-methyl-3-oxo-pentanoate, ethyl 2-ethylacetate, 4-methyl-3-oxo Methyl valerate, ethyl 3-oxohexanoate, ethyl 3-oxoethoxyvalerate, methyl 3-oxovalerate, methyl 3-oxohexanoate, 3-sided oxygen Ethyl heptanoate, methyl 3-oxoheptanoate, 4,4 a β-ketoester compound such as methyl dimethyl-3-oxovalerate; dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate , di-n-butyl malonate, di-tert-butyl malonate, di-n-hexyl malonate, tert-butyl malonate, diethyl malonate, ethyl malonate Ethyl ester, diethyl isopropyl malonate, diethyl n-butylmalonate, diethyl second butyl malonate, diethyl isobutylmalonate, 1-methylbutyl Malonic acid diester such as diethyl malonate.

In the case where the specific aluminum compound has an aluminum chelate structure, the number of the aluminum chelate structure is not particularly limited as long as it is from 1 to 3. Among them, from the viewpoint of storage stability, it is preferably 1 or 3, and more preferably 1 from the viewpoint of solubility. The number of aluminum chelate structures can be controlled, for example, by appropriately adjusting the ratio of mixing aluminum trialkoxide with 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.

From the viewpoint of the self-passivation effect and compatibility with a solvent contained as necessary, the specific aluminum compound preferably contains, in particular, an epoxy-containing ethyl aluminum diisopropylate and aluminum triisopropoxide. At least one of the groups, more preferably ethyl acetate ethyl diisopropylate.

The presence of the aluminum chelate structure in the specific aluminum compound and the presence of the alkoxide structure can be confirmed by the analysis 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.

In the case where the alumina precursor contains a specific aluminum compound, the content of the specific aluminum compound in the alumina precursor is, for example, preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95%. More than % by mass.

When the composition for forming a passivation layer contains an alumina precursor, the content of the alumina precursor in the composition for forming a passivation layer can be appropriately selected as needed. The content of the alumina precursor is preferably 0.1% by mass to 60% by mass, and more preferably 0.5%, based on the total mass of the composition for forming a passivation layer, from the viewpoint of the storage stability and the passivation effect. The mass % to 55% by mass, more preferably 1% by mass to 50% by mass, particularly preferably 1% by mass to 45% by mass.

When the composition for forming a passivation layer contains an alumina precursor, the content of the alumina precursor is not particularly limited. In the case where the total content of the compound of the formula (I) and the alumina precursor is 100% by mass, the content of the alumina precursor in the composition for forming a passivation layer is preferably, for example, 10% by mass to 99.5 by mass. More preferably, it is 25% by mass to 99% by mass, still more preferably 30% by mass to 98% by mass, and particularly preferably 30% by mass to 97% by mass. When the content of the alumina precursor is 10% by mass or more, the passivation effect tends to be improved. In addition, the storage stability of the composition for forming a passivation layer tends to be improved by setting the content of the alumina precursor to 99.5% by mass or less.

(Compound represented by the formula (III)) The composition for forming a passivation layer may further contain a compound represented by the following formula (III) (hereinafter also referred to as "the compound of the formula (III)"). By including the compound of the formula (III) in the composition for forming a passivation layer, a passivation layer having an excellent passivation effect can be formed. Further, the composition for forming a passivation layer may contain one compound of the formula (III), or may contain two or more kinds. When the composition for forming a passivation layer contains a compound represented by the formula (III), a larger negative fixed charge is exhibited, and the passivation effect tends to be further improved. In addition, when the composition for forming a passivation layer containing the compound represented by the general formula (III) is subjected to heat treatment (calcination), a composite oxide having a large refractive index tends to be formed. The passivation layer containing the composite oxide having a large refractive index tends to improve the power generation performance because sunlight is refracted at the interface with the semiconductor substrate, and sunlight is prevented from penetrating to the back side and then incident on the solar cell.

M(OR ⁶ ) _l (III)

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

In the formula (III), R ⁶ each independently represents an alkyl group, an aryl group or a fluorenyl group, preferably an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms or a carbon number of 1 to 10 carbon atoms. The mercapto group is more preferably an alkyl group having 1 to 8 carbon atoms, still more preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group represented by R ⁶ may be linear or branched. The alkyl group and the aryl group represented by R ⁶ may have a substituent or may be unsubstituted, and are preferably unsubstituted. The substituent of the alkyl group may, for example, be an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group or the like. The substituent of the aryl group may, for example, be a methyl group, an ethyl group, an isopropyl group, an amine group, a hydroxyl group, a carboxyl group, a sulfo group or a nitro group. The fluorenyl group represented by R ⁶ contains a carbonyl moiety and a hydrogen atom directly bonded to a carbon atom of the alkyl moiety, the aryl moiety or the carbonyl moiety. The alkyl moiety in the fluorenyl group represented by R ⁶ may be linear or branched. The alkyl moiety and the aryl moiety in the fluorenyl group represented by R ⁶ may have a substituent or may be unsubstituted, and are preferably unsubstituted. The substituent of the alkyl moiety in the fluorenyl group represented by R ⁶ may, for example, be an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group, a phenyl group or the like, and the substituent of the aryl moiety in the fluorenyl group represented by R ⁶ may be A methyl group, an ethyl group, an isopropyl group, an amine group, a hydroxyl group, a carboxyl group, a sulfo group, a nitro group, etc. are mentioned. Further, the carbon number of the alkyl group, the aryl group and the fluorenyl group represented by R ⁶ does not include the carbon number of the substituent. Specific examples of the alkyl group represented by R ⁶ include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a second butyl group, a tert-butyl group, a n-hexyl group, and an n-octyl group. , 2-ethylhexyl and 3-ethylhexyl, and the like. Specific examples of the aryl group represented by R ⁶ include a phenyl group and the like. Specific examples of the mercapto group represented by R ⁶ include a mercapto group, an ethenyl group, a benzamidine group, a 2-ethylhexyl group, and the like. Among them, from the viewpoint of the passivation effect, R ^{6 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 (III), l represents the valence of M. Here, from the viewpoint of reactivity with water, in the case where M is Nb, it is preferably 1 is 5; in the case where M is Ta, it is preferably 1 is 5; and M is VO. In the case, it is preferable that l is 3; in the case where M is Y, it is preferable that l is 3; and in the case where M is Hf, it is preferable that l is 4.

As the compound of the formula (III), M is preferably at least one selected from the group consisting of Nb, Ta and Y, and R ⁶ is an unsubstituted alkyl group having 1 to 4 carbon atoms.

The state of the compound of formula (III) may be either solid or liquid at 25 °C. The compound of the formula (III) is preferably a liquid at 25 ° C from the viewpoint of the storage stability of the composition for forming a passivation layer and the miscibility of the compound of the formula (I) and the alumina precursor.

Specific examples of the compound of the formula (III) wherein R ⁶ is an alkyl group include methoxy hydrazine, ethoxy hydrazine, isopropyl hydrazine, n-propoxy fluorene, n-butoxy fluorene, and tert-butoxy fluorene. , isobutoxy oxime, methoxy oxime, ethoxy ruthenium, isopropoxy oxime, n-propoxy oxime, n-butoxy ruthenium, tert-butoxy ruthenium, isobutoxy ruthenium, methoxy Base, ethoxylated oxime, oxime isopropoxide, ruthenium n-propoxide, ruthenium n-butoxide, ruthenium tert-butoxide, ruthenium isobutoxy hydride, methoxymethoxy vanadium, oxy ethoxy Vanadium, vanadium oxyisopropoxide, vanadium oxy-n-propoxide, vanadium oxy-n-butoxide, vanadium oxybutoxide, vanadium oxyisobutoxide, methoxy hydrazine, B Oxime, isopropoxy oxime, n-propoxy fluorene, n-butoxy fluorene, tert-butoxy fluorene, isobutoxy fluorene, etc., of which ethoxylated ruthenium and n-propoxy are preferred. Anthracene, n-butoxy fluorene, ethoxy hydrazine, n-propoxy hydrazine, n-butoxy hydrazine, isopropoxy hydrazine, and n-butoxy fluorene.

Specific examples of the compound of the formula (III) wherein R ⁶ is an aryl group include phenoxy hydrazine, phenoxy hydrazine, phenoxy hydrazine, phenoxy hydrazine and the like.

Examples of the compound of the formula (III) wherein R ⁶ is a fluorenyl group include cesium formate, cesium acetate, cesium 2-ethylhexanoate, cesium acetate, cesium 2-ethylhexanoate, cesium formate, cesium acetate, 2-ethylhexanoic acid. Barium, cesium formate, barium acetate, barium 2-ethylhexanoate, and the like.

Further, the compound of the formula (III) may be a manufacturer or a commercially available product. 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, tri-butoxy vanadium oxide.

The compound of the formula (III) 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 manufacturing method such as No. 227 593 and Japanese Patent Laid-Open No. Hei No. 3-291247.

A part of the compound of the formula (III) can also be obtained by mixing a compound of the formula (I) with a compound having a specific structure of two carbonyl groups to form a compound having a chelate structure, and comprising a composition for forming a passivation layer. in.

The presence of the alkoxide structure in the compound of the formula (III) 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 (III) contained in the composition for forming a passivation layer can be appropriately selected as needed. From the viewpoint of the passivation effect, the content of the compound of the formula (III) is preferably 0.1% by mass to 50% by mass, and more preferably 0.5% by mass, based on the total mass of the composition for forming a passivation layer. 30% by mass, more preferably 1% by mass to 20% by mass, particularly preferably 1% by mass to 10% by mass.

(矽 compound) The composition for forming a passivation layer may also contain a ruthenium compound. The ruthenium compound can be controlled by physical or chemical interaction or chemical bonding with a compound of the formula (I), an alumina precursor, a compound of the formula (III), a resin, a liquid medium or the like in the composition for forming a passivation layer. The surface tension of the composition for forming a passivation layer. Thereby, the thickness unevenness of the composition layer as a coating film is suppressed, and the variation of the thickness of the formation of the passivation layer is suppressed. Further, generation of voids in the heat-treated material layer (calcined material layer) of the composition for forming a passivation layer is suppressed, and the denseness of the passivation layer is improved to form a homogeneous passivation layer, so that an excellent passivation effect is obtained.

The ruthenium compound is not particularly limited as long as it contains a ruthenium atom in the molecule. From the viewpoint of easiness of preparation of the composition for forming a passivation layer, the ruthenium compound is preferably a compound in which an oxygen atom is bonded to a ruthenium atom. The compound in which the oxygen atom is bonded to the ruthenium atom can form a complex with at least one selected from the group consisting of an organic compound and an inorganic compound. Specific examples of the ruthenium compound include a decyl alkoxide, a phthalate compound, an eucalyptus oil having a decane bond, a decane resin, and the like. Among them, a decoxide alkoxide, a citrate compound, and the like are preferable. Oyster sauce. Emu oil can also be a copolymer of a compound having a decane bond with other compounds. The stanol alkoxide and the citrate compound may also be oligomers.

The oligomer of the phthalate compound is a phthalate compound represented by the following formula (IV). Si _k O _{k -1} (R ⁷ O) _{2( k +1)} (IV) In the formula (IV), R ⁷ represents an alkyl group having 1 to 8 carbon atoms. k represents an integer of 1 to 10. Examples of the phthalate compound include methyl phthalate, ethyl decanoate, isopropyl decanoate, n-propyl decanoate, n-butyl decanoate, n-pentyl citrate, and acetamidine. Sulfate and the like.

Further, the phthalate compound may be an oligomer of a phthalate compound, and is commercially available as Fuso Chemical Industry Co., Ltd., Tama Chemical Industry Co., Ltd., and COLCOAT Co., Ltd. Wait for the market. Specific examples of the methyl phthalate and the oligomer thereof include those produced by Fuso Chemical Industry Co., Ltd. or manufactured by Colcote Co., Ltd., which are manufactured by Kelkote Co., Ltd. Methyl phthalate 53A and the like. Specific examples of the ethyl decanoate and the oligomer thereof include ethyl phthalate 40 manufactured by Tama Chemical Industry Co., Ltd. or manufactured by Cole Co., Ltd., and B manufactured by Tama Chemical Industry Co., Ltd. A bismuth citrate 45, an ethyl phthalate 28 manufactured by Colecote Co., Ltd., an ethyl citrate 48 or the like. Specific examples of the other phthalate and the oligomer thereof include N-propyl citrate and N-butyl citrate manufactured by Colecote Co., Ltd., and the like.

The ruthenium compound preferably contains a ruthenate compound from the viewpoint of suppressing generation of voids in the heat-treated material layer (calcined layer) and improving the density of the passivation layer. The bismuth citrate compound has a gentle reaction with the compound of the formula (I) in the heat treatment (calcination) as compared with the decyl alkoxide, and can suppress the reaction to a specific temperature state. From this, it is presumed that the reaction occurs uniformly, and generation of voids in the heat-treated material layer (calcined material layer) can be suppressed, and the denseness of the passivation layer is improved.

The phthalate compound is preferably an ethyl phthalate compound or an ethyl phthalate oligomer from the viewpoint of lowering the surface tension of the composition for forming a passivation layer and improving printability.

The plurality of R ⁷ O groups of the citrate compound may be the same or different. The R ⁷ O group preferably contains a methoxy group and an ethoxy group. In the case where the phthalate compound has a methoxy group and an ethoxy group, the ratio of the number of equivalents of the methoxy group to the number of equivalents of the ethoxy group (methoxy/ethoxy group) is preferably, for example, 30/70 to ～. 70/30, more preferably 40/60 to 60/40, still more preferably 45/55 to 55/45, and particularly preferably the equivalent number of methoxy groups is equivalent to the equivalent number of ethoxy groups. . As the phthalate compound having a methoxy group and an ethoxy group in substantially the same amount, for example, EMS-485 manufactured by Colecote Co., Ltd. can be cited.

The phthalate compound may be used alone or in combination of two or more. Further, the citrate compound may be used in combination with water, a catalyst, a liquid medium or the like as needed.

The stankan alkoxide is not particularly limited as long as it has a ruthenium atom and an alkoxy group bonded to a ruthenium atom. Specific examples of the stankan alkoxide include a compound represented by the following formula (V), a decane coupling agent, and the like. R _n Si(OR ⁸ ) _4-n (V)

In the general formula (V), R represents an alkyl group or an aryl group, an aryl group, and may have a substituent group, R ⁸ represents a saturated or unsaturated carbon atoms of the hydrocarbon group having 1 to 6 carbon atoms or by 1 ~ a 6-carbon group having 1 to 6 carbon atoms substituted by an alkoxy group. n represents 1 to 3, preferably 1 or 2. The alkyl group represented by R in the formula (V) preferably has 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, still more preferably 1 to 3 carbon atoms. The aryl group represented by R in the formula (V) preferably has a carbon number of 6 to 14, more preferably a phenyl group. In the general formula (V), examples of the substituent which the alkyl group represented by R may have include a fluorine atom, a (meth)acryloxy group, a vinyl group, an epoxy group, a styryl group, an amine group and the like. The amine group may further have a substituent, and examples of the amine group having a substituent include N-2-(aminoethyl)-3-amine group, N-phenyl-3-amino group and the like. The saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms represented by R ⁸ in the above formula (V) may, for example, be a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a butyl group or an isobutyl group. Tributyl, pentyl, cyclohexyl and the like.

Further, the hydrocarbon group having 1 to 6 carbon atoms which is substituted by the alkoxy group having 1 to 6 carbon atoms represented by R ⁸ in the formula (V) may, for example, be a methoxymethyl group, a methoxyethyl group or an ethoxy group. Methyl, ethoxyethyl, methoxypropyl, ethoxypropyl, propoxypropyl and the like.

The stankan alkoxide preferably contains a decane coupling agent from the viewpoint of improvement in the printability and the compactness of the passivation layer. The decane coupling agent is not particularly limited as long as it is a compound having an organic functional group other than a halogen atom, an alkoxy group, and an alkoxy group in one molecule. The decane coupling agent may be used alone or in combination of two or more. Examples of the stankan alkoxide include the following compounds (a) to (g) containing a decane coupling agent. (a) 3-propenyloxypropyltrimethoxydecane, 3-methacryloxypropylmethyldimethoxydecane, 3-methylpropenyloxypropyltrimethoxydecane, 3 a stanol alkoxide having a (meth) acryloxy group, such as methacryloxypropyl dimethyl diethoxy decane or 3-methyl propylene oxypropyl triethoxy decane (b) 3-glycidoxypropyltrimethoxydecane, 3-glycidoxypropylmethyldimethoxydecane, 2-(3,4-ethoxycyclohexyl)ethyltrimethoxydecane, etc. Cycloalkane of epoxy or glycidoxy (c) N-2-(aminoethyl)-3-aminopropyltrimethoxydecane, N-2-(aminoethyl)-3- a decyl alkoxide having a mercapto group such as a decyl alkoxide having an amine group such as aminopropylmethyldimethoxydecane or 3-aminopropyltriethoxydecane (d) 3-mercaptopropyltrimethoxydecane (e) methyltrimethoxydecane, dimethyldimethoxydecane, methyltriethoxydecane, dimethyldiethoxydecane, n-propyltrimethoxydecane, n-propyltriethoxy Base decane, hexyltrimethoxydecane, hexyltriethoxy a decyl alkoxide having an alkyl group such as decane, octyltriethoxydecane, decyltrimethoxydecane or 1,6-bis(trimethoxydecyl)hexane; (f) phenyltrimethoxydecane, a decyl alkoxide having a phenyl group, a decyl alkoxide having a phenyl group such as phenyltriethoxydecane (g), a trifluoropropyltrimethoxydecane or the like

The stanol alkoxide preferably comprises a stanol alkoxide having a propylene methoxy group, a methacryloxy group, an epoxy group, an alkyl group, or a trifluoroalkyl group. Further, the stankan alkoxide may be used in combination with water, a catalyst, a liquid medium or the like as needed.

There are no special restrictions on oyster sauce. Specific examples of the eucalyptus oil include dimethyl hydrazine oil, methyl hydroquinone oil, methyl phenyl hydrazine oil, alkyl modified eucalyptus oil, polyether modified eucalyptus oil, alcohol modified eucalyptus oil, fluorine modified eucalyptus oil, and amine modified eucalyptus oil. Sulfhydryl modified eucalyptus oil, epoxy modified eucalyptus oil, carboxyl modified eucalyptus oil, higher fatty acid modified eucalyptus oil, Carnauba modified eucalyptus oil, guanamine modified eucalyptus oil, free radical reactive base eucalyptus oil, terminal reaction Sputum oil, ionic oil-containing eucalyptus oil, etc.

The content of the cerium compound is, for example, preferably 0.01% by mass to 35% by mass, more preferably 0.05% by mass to 30% by mass, even more preferably 0.1%, based on the total mass of the composition for forming a passivation layer. The mass % to 20% by mass, particularly preferably 0.1% by mass to 10% by mass. When the content of the ruthenium compound is 0.01% by mass or more, the surface tension of the composition for forming a passivation layer tends to be lowered, and the printability tends to be improved. When the content of the ruthenium compound is 35% by mass or less, the passivation effect tends to be more sufficiently obtained.

The content of the ruthenium atoms in the composition for forming a passivation layer is preferably 0.001% by mass to 15% by mass, more preferably 0.01% by mass to 10% by mass, still more preferably 0.05% by mass to 5% by mass.

(Resin) The composition for forming a passivation layer may further contain a resin. The composition of the passivation layer-forming composition contains a resin, and the shape stability of the composition layer formed by imparting the composition for forming a passivation layer onto the semiconductor substrate is further improved, and the desired layer can be formed in a region where the composition layer is formed. The passivation layer is selectively formed in a desired shape.

The kind of the resin is not particularly limited. It is preferable that the resin is adjusted to a range in which a favorable pattern can be formed when the composition for forming a passivation layer is applied to the semiconductor substrate. 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, 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 at least one of an acryl group and a methacryl group, and the "(meth) acrylate" means acrylate and methacrylate. At least one of them.

From the viewpoint 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 it is possible to easily adjust viscosity and thixotropy even in a small amount. From the standpoint of consideration, 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, for example, 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 was 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 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, as described above, the thixotropy of the composition is improved by the action of water on the compound of the formula (I), so that the composition for forming a passivation layer containing water exhibits thixotropic properties by the resin. The necessity is not high. Therefore, the content of the resin contained in the composition for forming a passivation layer containing water is, for example, 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.

(High-boiling material) In the composition for forming a passivation layer, 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, in order to maintain the shape after the composition for forming a passivation layer is applied to the semiconductor substrate, the high boiling point material preferably has a high viscosity. Examples of the material satisfying these include isobornylcyclohexanol.

Isobornylcyclohexanol is commercially available, for example, 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 application to the semiconductor substrate.

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

(Liquid Medium) The composition for forming a passivation layer may further contain a liquid medium (solvent or dispersion medium). When the composition for forming a passivation layer contains a liquid medium, the viscosity is more easily adjusted, and the impartability is further improved, and a more uniform passivation layer tends to be formed. The liquid medium is not particularly limited and may be appropriately selected as needed. The liquid medium is preferably a liquid medium comprising a compound which dissolves the compound of the formula (I), optionally added an alumina precursor and a compound of the formula (II) to obtain a uniform solution, and 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-pentyl Ketone solvent such as diketone or acetonylacetone; diethyl ether, methyl ethyl ether, methyl n-propyl ether, diisopropyl ether, tetrahydrofuran, methyl tetrahydrofuran, dioxane, dimethyl dioxane, Diol 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 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 Base-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 Ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol methyl-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 Ethyl 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 methyl-n-butyl ether, tetrapropylene glycol Ether solvent such as methyl-n-hexyl ether or tetrapropylene glycol di-n-butyl ether; methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, and second butyl acetate , n-amyl acetate, second amyl acetate,-3-methoxybutyl acetate, acetic acid Amyl amyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 2-(2-butoxyethoxy)ethyl acetate, benzyl acetate, cyclohexyl acetate, acetic acid Cyclohexyl ester, decyl acetate, methyl acetate, ethyl acetate, diethylene glycol methyl ether, diethylene glycol monoethyl ether, dipropylene glycol methyl ether, dipropylene glycol diethyl ether, diacetic acid Ethylene glycol ester, methoxytriethylene glycol acetate, isoamyl acetate, ethyl propionate, n-butyl propionate, isoamyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate Ethyl lactate, n-butyl lactate, n-amyl lactate, ethylene glycol methyl ether propionate, ethylene glycol ethyl ether propionate, ethylene glycol methyl ether acetate, ethylene glycol ethyl ether acetate, propylene glycol Ester solvent such as methyl ether acetate, propylene glycol diethyl ether acetate, propylene glycol propyl ether acetate, γ-butyrolactone, γ-valerolactone; acetonitrile, N-methylpyrrolidone, N-ethylpyrrolidine Ketone, N-n-propyl pyrrolidone, N-n-butyl pyrrolidone, N-n-hexyl pyrrolidone, N-cyclohexyl pyrrolidone, N,N-dimethylformamide, N,N - dimethyl acetamide, dimethyl An aprotic polar solvent such as ketone; a hydrophobic organic solvent such as dichloromethane, chloroform, dichloroethane, benzene, toluene, xylene, hexane, octane, ethylbenzene or 2-ethylhexanoic acid; Methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, second butanol, tert-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-undecyl alcohol, trimethyl decyl alcohol, second-tetradecanol, second heptadecyl alcohol, cyclohexanol, methyl An alcohol solvent such as cyclohexanol, benzyl alcohol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol or tripropylene glycol; a phenol solvent such as cresol 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 single n-Hexyl Ether, Ethylene Triglycol, Tetraethylene Glycol Single Positive a glycol monoether solvent such as ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether or tripropylene glycol monomethyl ether; terpinene, terpineol, laurylene, allo-ocimene, limonene, dipentane A terpene solvent such as an alkene, a terpene, a sulphonone, a ocimene or a celery. These liquid mediums may be used alone or in combination of two or more.

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

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 impartability and pattern formation property of the composition for forming a passivation layer, 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, it is 10% by mass to 95% by mass.

(Acid Compound and Basic Compound) The composition for forming a passivation layer may further contain at least one of an acidic compound and 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, for example, the total mass of the composition for forming a passivation layer, from the viewpoint of storage stability. It is preferably 1% by mass or less, and 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 Brucelle base and 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.

(Other metal compound) The composition for forming a passivation layer may further contain Bi, Al, Nb, and Ta in addition to the compound of the formula (I), the aluminum oxide precursor or the compound of the formula (III), and the ruthenium compound, which are optionally contained. Other metal compounds of metal elements other than V, Y and Hf. Examples of the other metal compound include a metal alkoxide such as a metal alkoxide other than Bi, Al, Nb, Ta, V, Y, and Hf, and a metal complex such as a chelate complex, and an organometallic compound. The other metal compounds may be used alone or in combination of two or more. When the composition for forming a passivation layer contains another metal compound, a larger negative fixed charge appears, and the passivation effect tends to be further improved. Further, when the composition for forming a passivation layer containing another metal compound is subjected to heat treatment (calcination), a composite oxide having a large refractive index tends to be formed. The passivation layer containing the composite oxide having a large refractive index tends to improve the power generation performance because sunlight is refracted at the interface with the semiconductor substrate, and sunlight is prevented from penetrating to the back side and then incident on the solar cell.

From the viewpoint of the reactivity of the compound of the formula (I), the alumina precursor to be contained, the compound of the formula (III) and the ruthenium compound, the other metal compound preferably contains a metal alkoxide. The metal alkoxide is not particularly limited as long as it is a compound obtained by reacting an atom of a metal with an alcohol. Specific examples of the metal alkoxide include compounds represented by the following formula (VI). M ² (OR ⁹ ) _t (VI)

In the above formula (VI), M ² represents a metal element having a valence of from 1 to 7 (excluding Bi, Al, Nb, Ta, V, Y and Hf). Specifically, M ² may be selected from the group consisting of Li, Na, K, Mg, Ca, Sr, Ba, La, Ti, B, Zr, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Zn, and At least one metal element of the group formed by Pb. Wherein the self-generating efficiency of the solar cell element constituting the case where the viewpoint, M ² is preferably selected from the group consisting of Li, Na, K, Mg, Ca, Sr, Ba, La, Ti, B, Zr, Mo, Co At least one metal element of the group consisting of Zn and Pb is more preferably at least one metal element selected from the group consisting of Ti and Zr.

In the above formula (VI), R ⁹ represents a saturated or unsaturated hydrocarbon group having 1 to 6 carbon atoms or a hydrocarbon group having 1 to 6 carbon atoms substituted by an alkoxy group having 1 to 6 carbon atoms. t represents the valence of M ² .

The group represented by R ⁹ in the above formula (VI) may be the same one as the group represented by R ⁸ in the above formula (V).

The composition for forming a passivation layer may further comprise a reactant of at least one of the compound of the formula (I) and optionally an alumina precursor, a compound of the formula (III), an anthracene compound and another metal compound. In order to obtain such a reactant, water may be added to the composition for forming a passivation layer. For example, when the alumina precursor, the ruthenium compound, and the other metal compound contained in the case are each an alkoxide, the hydrolysis reaction is carried out by adding water, and the thixotropy is improved, and the composition for forming a passivation layer can be formed. Improved printability.

(Other components) The composition for forming a passivation layer may further contain other components generally used in the field, in addition to the above components. Examples of the other component include a thixotropic agent such as an organic filler, an inorganic filler, and an organic acid salt (excluding water, a hydrolyzate of the compound of the formula (I), a hydrolyzate of the alumina precursor, and a hydrolyzate of the compound of the formula (III), Wetting promoters, leveling agents, surfactants, plasticizers, fillers, defoamers, stabilizers, antioxidants and perfumes. In the case where the composition for forming a passivation layer contains other components, the content of the other components is not particularly limited, and may be, for example, 0.01 parts by mass to 20 parts by mass per 100 parts by mass of the total amount of the composition for forming a passivation layer. Use ingredients for each part. The other components may be used alone or in combination of two or more.

Moreover, other ingredients preferably comprise at least one thixotropic agent. By including at least one thixotropic agent, the shape stability of the composition layer formed by imparting the composition for forming a passivation layer onto the semiconductor substrate can be further improved, and can be desired in a region where the composition layer is formed. The location selectively forms a passivation layer in a desired shape.

Examples of the thixotropic agent include a fatty acid guanamine, a polyalkylene glycol compound, an organic filler, an inorganic filler, and the like. Specific examples of the polyalkylene glycol compound include compounds represented by the following formula (VII).

R ¹⁰ -(OR ¹¹ ) _n -OR ¹² ···(VII)

In the formula (VII), R ¹⁰ and R ¹² each independently represent a hydrogen atom or an alkyl group, and R ¹¹ represents an alkylene group. n is an arbitrary integer of 3 or more. Furthermore, R ¹¹ in a plurality of (OR ¹¹ ) present may be the same or different.

Specific examples of the fatty acid decylamine include compounds represented by the following general formula (1), formula (2), formula (3), and formula (4).

R ¹³ CONH ₂ ····(1) R ¹³ CONH-R ^{1 4} -NHCOR ¹³ ····(2) R ¹³ NHCO-R ^{1 4} -CONHR ¹³ ····(3) R ¹³ CONH-R ^{1 4} -N(R ^{1 5} ) ₂ ····(4)

In the formula (1), the formula (2), the formula (3) and the formula (4), R ¹³ and R ^{1 5} each independently represent an alkyl group or an alkenyl group having 1 to 30 carbon atoms, and R ^{1 4} It represents an alkylene group having 1 to 10 carbon atoms. R ¹³ and R ^{1 5} may be the same or different.

Examples of the organic filler include an acrylic resin, a cellulose resin, and a polystyrene resin.

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.

Further, the composition for forming a passivation layer may contain an oxide of Bi together with the compound of the formula (I). Since the oxide of Bi 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 an oxide of Bi exhibits an excellent passivation effect. Further, the passivation layer-forming composition may further contain at least one oxide selected from the group consisting of Nb, Ta, V, Y, and Hf together with a specific aluminum compound or a compound of the formula (III) (hereinafter referred to as "specific Oxide"). The specific oxide is an oxide formed by heat-treating (calcining) a specific aluminum compound or a compound of the formula (III), and therefore it is expected that a passivation layer formed of a composition for forming a passivation layer containing a specific oxide serves as an excellent passivation effect. .

(Physical property value) The viscosity of the composition for forming a passivation layer is not particularly limited, and can be appropriately selected depending on the method or the like applied to the semiconductor substrate. For example, the viscosity of the composition for forming a passivation layer is preferably from 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 more preferably from 0.1 Pa·s to 10,000 Pa·s. Further, in the present specification, the viscosity is measured using a rotary shear viscometer at 25 ° C and a shear rate of 1.0 s ^-1 .

The shear viscosity of the composition for forming a passivation layer is not particularly limited, and is preferably thixotropy. Wherein, from the viewpoint of the pattern formability, shear viscosity at a shear rate of 1.0 s ^-1 shear viscosity [eta] _a shear rate of 10 s ^-1 divided by the calculated η ₂ thixotropic ratio (η ₁ / η ₂ For example, it is preferably 1.05 to 100, more preferably 1.1 to 50. Further, in the present specification, the shear viscosity is measured at a temperature of 25 ° C using a rotary shear viscometer equipped with a cone plate (having a diameter of 50 mm and a cone angle of 1 °).

On the other hand, in the case where the passivation layer is formed containing a high-boiling material in place of the resin composition, from the viewpoint of the pattern formability, shear rate of 1.0 s ^-1 to shear viscosity η ₁ divided by the shear rate 1000 s ^{- 1} shear viscosity η ₃ is calculated, for example, a thixotropic preferred ratio is 1.05 to 100 (η ₁ / η _3), more preferably 1.1 to 50.

The preparation method of the composition for forming a passivation layer is not particularly limited. For example, it can be produced by mixing a compound of the formula (I), optionally containing water, an alumina precursor, a compound of the formula (III), a liquid medium, a resin or the like by a mixing method which is usually used. In the case of preparing a composition for forming a passivation layer containing a resin and a liquid medium, the resin may be dissolved in a liquid medium, and then mixed with a compound of the formula (I) or the like to prepare a composition for forming a passivation layer. .

In the case where a specific aluminum compound is used as the alumina precursor, the aluminum alkoxide may be prepared by mixing with a compound which can form a chelate with aluminum. In this case, a liquid medium can be suitably used, and heat treatment can also be performed.

Further, the components contained in the composition for forming a passivation layer and the content of each component can be subjected to thermal analysis such as differential thermal-thermal weight simultaneous measurement apparatus (TG/DTA), nuclear magnetic resonance (NMR), and infrared spectroscopy (IR). It is confirmed by isospectral analysis, chromatographic analysis such as high performance liquid chromatography (HPLC) or gel permeation chromatography (GPC).

<Semiconductor Substrate with Passivation Layer> The semiconductor substrate with a passivation layer of the present embodiment includes: a semiconductor substrate; and a passivation layer which is a passivation layer of the present embodiment provided on at least a part of at least one surface of the semiconductor substrate A heat-treated product of the composition is formed. The semiconductor substrate with a passivation layer may further include other constituent elements as needed. The semiconductor substrate with a passivation layer exhibits an excellent passivation effect by including 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. Examples of the semiconductor substrate include those in which a p-type impurity or an n-type impurity is doped (diffused) in a substrate such as ruthenium or iridium. The semiconductor substrate is preferably a tantalum substrate. 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 is preferably from 50 μm to 1000 μm, more preferably from 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, the average thickness of the passivation layer is preferably 200 nm or less, more preferably 5 nm to 200 nm, still more preferably 10 nm to 190 nm, and particularly preferably 15 nm to 180 nm. Furthermore, the average thickness of the passivation layer formed can be determined by a conventional method using an automatic ellipsometer (for example, Five Labs, MARY-102), and the arithmetic mean is calculated. Calculated by value.

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 power generation performance can be obtained by being applied to a solar cell element. In the case where a semiconductor substrate with a passivation layer is applied to a solar cell element, the passivation layer is preferably provided on the light-receiving surface side of the 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; and 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 an excellent passivation effect can be formed by a simple method.

The semiconductor substrate to which the passivation layer is formed can be used as described in the semiconductor substrate with the passivation layer.

The method for producing a semiconductor substrate with a passivation layer preferably further includes the step of providing an alkaline aqueous solution on the semiconductor substrate before the step of forming the composition layer. That is, it is preferable to clean the surface of the semiconductor substrate with an alkaline aqueous solution before applying the composition for forming a passivation layer on the semiconductor substrate. By washing with an alkaline aqueous solution, organic substances, particles, and the like 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 washing time is, for example, preferably from 10 seconds to 10 minutes, more preferably from 30 seconds to 5 minutes.

A known coating method or the like can be used as the step of forming a composition layer for forming a composition for forming a passivation layer on a semiconductor substrate. Specific examples thereof include a dipping method, a 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 printing method such as screen printing, an inkjet method, or the like is preferable, and a screen printing method is more preferable.

The amount of the composition for forming a passivation layer 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 the desired thickness.

By heat-treating (calcining) the composition layer formed of the composition for forming a passivation layer, a heat-treated material layer (calcined material layer) derived from the composition layer is formed, whereby a passivation layer can be formed on the semiconductor substrate. Heat treatment (calcination) conditions of the composition layer, if the compound of the formula (I) contained in the composition layer, the aluminum oxide precursor contained in the composition, and the compound of the formula (III) are converted into a heat-treated product (calcined product) The metal oxide or composite oxide is not particularly limited. 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, and is, for example, preferably from 30 seconds to 10 hours, more preferably from 1 minute to 5 hours.

The method for producing a semiconductor substrate with a passivation layer may further include passivation of the passivation layer after the step of forming a composition layer by applying a composition for forming a passivation layer onto the semiconductor substrate to form a passivation layer by heat treatment (calcination). The step of drying the composition layer of the layer forming composition. 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 is not particularly limited as long as 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 contained in the composition for forming a passivation layer can be removed. The drying treatment is preferably carried out by heat treatment at 30 ° C to 600 ° C for 5 seconds to 60 minutes, and more preferably at 40 ° C to 450 ° C for 30 seconds 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 may be followed by forming a composition layer by providing a composition for forming a passivation layer, and then forming a passivation layer by heat treatment (calcination). Before the step, the step of degreasing the composition layer is 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 is preferably carried out by heat treatment at 30 ° C to 600 ° C for 5 seconds to 60 minutes, and more preferably at 40 ° C to 450 ° C for 30 seconds to 40 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 surface of the heat-treated material 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 component 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, it is excellent in power generation performance.

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

Moreover, the thickness of the passivation layer formed on the semiconductor substrate can be appropriately selected depending on the purpose. For example, the average thickness of the passivation layer is preferably 5 nm to 200 nm, more preferably 10 nm to 190 nm, still more preferably 15 nm to 180 nm. The shape and size of the solar cell elements 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 heat-treating (calcining) the composition layer to form a passivation layer; and at least a portion of the p-type layer and the n-type layer The step of arranging the electrodes on one 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 excellent in power generation performance 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 may be a p-type layer or an n-type layer. Among them, from the viewpoint of power generation performance, the surface of the semiconductor substrate is preferably a p-type layer. The details of the method of forming the passivation layer using the composition for forming a passivation layer are the same as the method of manufacturing the semiconductor substrate with the passivation layer, and preferred embodiments are also the same.

Next, a method of manufacturing the solar cell element of the present embodiment will be described with reference to the drawings, but the present invention is not limited thereto. Furthermore, the size of the members in the respective drawings is the size of the concept, and the relative relationship between the sizes of the members is not limited thereto. 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) to (9) of FIG. 1 are a cross-sectional view showing a step of an example of a method of manufacturing a solar cell element including a passivation layer. However, the step chart does not impose any limitation on the present invention.

In (1) of FIG. 1, the p-type semiconductor substrate 1 is cleaned by an alkaline aqueous solution, and organic substances, particles, and the like on the surface of the p-type semiconductor substrate 1 are removed. 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 "texture structure") on the surface. Thereby, the reflection of sunlight can be suppressed on the light receiving surface side. Further, an etching solution containing NaOH and IPA (isopropyl alcohol) can be used in the alkaline etching.

Then, as shown in (3) of FIG. 1, 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 is formed in the p-type body portion. The boundary forms a pn junction.

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 (3) of FIG. 1, an n ⁺ -type diffusion layer is formed on the back surface and the side surface (not shown) in addition to the light-receiving surface (surface). 2. Further, a PSG (Phosphosilicate 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 (4) of FIG. 1, 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 (5) of FIG. 1 , 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 (6), as shown in FIG. 1, on the light-receiving surface of n ⁺ type diffusion layer 2, by plasma CVD (plasma chemical vapor deposition strengthening (Plasma Enhanced Chemical Vapor Deposition, PECVD )) method or the like, An anti-reflection film 4 such as tantalum nitride is provided to have a thickness of about 90 nm.

Further, regarding the back surface, an uneven aqueous solution such as NaOH may be used to flatten the unevenness on the back surface.

Then, as shown in FIG. 1 (7), a composition for forming a passivation layer is applied to a part of the back surface by a screen printing method or the like, and then dried at a temperature of 300 to 900 ° C after drying ( The passivation layer 5 is formed by 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 FIGS. 7 and 8 that in the subsequent step, the portion where the back surface output extraction electrode 7 is formed is removed, and the passivation of the back surface is formed in a dot pattern. Layer 5. 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 dot diameter (L _a ) and the dot interval (L _b ) can be arbitrarily set, but from the viewpoint of self-passivation effect and suppression of recombination of minority carriers, for example, L _a is preferably 5 μm to 2 mm and L _b of 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, the recombination of a minority carrier is effectively suppressed, and the power generation efficiency of the solar cell element is improved.

Further, another example of the pattern of formation of the passivation layer on the back surface is shown as a schematic plan view. Fig. 9 is a schematic plan view showing an enlarged portion A of Fig. 5; Fig. 10 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, as shown in FIGS. 9 and 10, 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 line. The pattern of the shape forms a passivation layer 5 on the back side. The pattern of the linear opening portion is preferably defined by a line width (L _c ) and a line interval (L _d ), and is regularly arranged. The line width (L _c ) and the line spacing (L _d ) can be arbitrarily set, but from the viewpoint of self-passivation effect and suppression of recombination of minority carriers, for example, L _c is preferably 1 μm to 300 μm and L _d is 500 μm ~ 5000 μm, more preferably is L _c of 10 μm ~ 200 μm and L _d is 600 μm ~ 3000 μm, further more preferably it is L _c of 30 μm ~ 150 μm and L _d is 700 μm ~ 1500 Mm.

When the composition for forming a passivation layer has excellent pattern formability, the pattern of the linear opening portion arranges the line width (Lc) and the line interval (Ld) more regularly. Therefore, the recombination of a minority carrier is effectively suppressed, and the power generation efficiency of the solar cell element is improved.

Here, a passivation layer forming composition is applied to a portion (a portion other than the opening) where the passivation layer is to be formed, and heat treatment (baking) is performed to form a passivation layer having a desired shape. On the other hand, a composition for forming a passivation layer may be provided on the entire surface, and after the heat treatment (calcination), the passivation layer in the opening portion may be selectively removed by laser or photolithography to form an opening. In addition, a portion of the opening portion that is not intended to be coated with the composition for forming a passivation layer may be masked in advance by a masking material to selectively impart a composition for forming a passivation layer.

Then, as shown in (8) of FIG. 1 , a silver electrode paste containing glass particles is applied 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. . In addition, in FIG. 4, two light-receiving surface output extraction electrodes 9 are provided, but the number of light-receiving surface output extraction electrodes 9 may be three or more from the viewpoint of extraction efficiency (power generation efficiency) of a few carriers. .

On the other hand, as shown in (8) of FIG. 1 , an aluminum electrode paste 6 containing glass powder and a silver electrode paste containing glass particles are applied to the back surface by screen printing or the like. Fig. 11 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 output extraction electrode 9 form a back surface current collecting aluminum electrode 6 and a back surface output extraction electrode 7 on the back surface.

After heat treatment (calcination), as shown in (9) of FIG. 1, the glass particles contained in the silver electrode paste forming the light-receiving surface electrode react with the anti-reflection film 4 (burn-through) on the light-receiving surface, and receive light. The surface electrode (the light-receiving surface current collecting electrode 8 and the light-receiving surface output extraction electrode 9) is electrically connected (ohmic contact) to the n ⁺ -type diffusion layer 2 . On the other hand, in the back surface, aluminum in the aluminum electrode paste 6 is diffused into the p-type semiconductor substrate 1 by heat treatment (calcination) from a portion of the dot-like or linear portion where the passivation layer 5 is not formed. A p ⁺ -type diffusion layer 10 is formed. By using a composition for forming a passivation layer having excellent 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.

(10) to (18) of FIG. 2 are a cross-sectional view showing another example of a method of manufacturing a solar cell element including a passivation layer, and the n ⁺ type diffusion on the back surface is performed by an etching process. After the layer 2 is removed, the back surface is further flattened, and the solar cell element can be produced in the same manner as (1) of FIG. 1 to (9) of FIG. 1 . 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.

(19) to (29) of FIG. 3 are a cross-sectional view showing a step of another example of a method of manufacturing a solar cell element including a passivation layer. In this method, the steps of forming the texture structure, the n ⁺ -type diffusion layer 2 and the anti-reflection film 4 on the p-type semiconductor substrate 1 ((19) to (24) of FIG. 3) and FIG. 1 The method of (1) to (9) of FIG. 1 is the same.

After forming the anti-reflection film 4, as shown in (25) of FIG. 3, after the composition for forming a passivation layer is applied, after drying, heat treatment (baking) is performed at 300 to 900 ° C to form a passivation layer 5 . . Another example of the pattern of formation 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 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 portions where the rear-side output electrodes are formed.

Thereafter, as shown in (26) of FIG. 3, boron or aluminum is diffused from a dot-like or linear portion where the passivation layer 5 is not formed, to form the p ⁺ -type diffusion layer 10 on the back surface. 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 the gas is diffused in the same manner as in 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 p-type semiconductor substrate 1. 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 an aluminum paste to the entire surface or the opening of the back surface and heat-treating (calcining) at 450 to 900 ° C can be used. The aluminum is diffused from the opening to form the p ⁺ -type diffusion layer 10, and then the heat-treated layer (calcined layer) containing the aluminum paste on the p ⁺ -type diffusion layer 10 is etched by hydrochloric acid or the like.

Then, as shown in (27) of FIG. 3, 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 (28) of FIG. 3, a silver electrode paste containing glass particles is applied to the light-receiving surface by screen printing or the like, and a silver electrode containing glass particles is applied to the back surface by a screen printing method or the like. paste. 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. 11, and is given a pattern.

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, as shown in (29) of FIG. 3 . 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.

Further, (1) to (1) of FIG. 1 to (19) of FIG. 3 to (29) of FIG. 3 show that after the passivation layer 5 is formed on the back surface, the aluminum electrode 6 for back surface current collection is formed. Alternatively, the passivation layer 5 may be formed after the formation of the back surface current collecting aluminum electrode 6 or the back surface collecting aluminum electrode 11 by the method of the back surface collecting aluminum electrode 11.

Further, the method of forming the passivation layer 5 on the back surface is shown in (1) to (1) of FIG. 1 to (19) of FIG. 3 to (29) of FIG. 3, and may be omitted from the p-type semiconductor substrate 1. In addition to the back surface, a composition for forming a passivation layer is applied to the side surface, and heat treatment (baking) is performed to form a passivation layer 5 (not shown) on the side surface (edge) of the p-type semiconductor substrate 1. Thereby, a solar cell element having more excellent power generation efficiency can be manufactured. Further, the passivation layer 5 may be formed on the back surface, and the passivation layer forming composition of the present embodiment may be applied only to the side surface, and heat-treated (calcined) may be performed to form the passivation layer 5. When the composition for forming a passivation layer of the present embodiment is used for a position having a large number of crystal defects such as a side surface, the effect is particularly large.

FIGS. 1(1) to 1(9) to 3(19) to 3(29) show an example in which a p-type semiconductor substrate 1 is used as a semiconductor substrate, and an n-type semiconductor substrate is used. Next, a solar cell element excellent in conversion efficiency can be manufactured based on the above.

<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 may further be connected to a plurality of solar cell elements via a wiring material as needed, or may be formed by sealing 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. The size of the solar cell is not limited, and is preferably, for example, 0.5 m ² to 3 m ² . [Examples]

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

<Example 1> (Preparation of composition 1 for passivation layer formation) 8.8926 g of tris(2-ethylhexanoate) ruthenium (Azmax Co., Ltd., structural formula: Bi (OCOCHC ₂ H) ₅ C ₄ H ₉ ) ₃ , Molecular weight: 638.6), 3.8224 g of ethyl acetate ethyl diisopropylate (Kawasaki Seiki Co., Ltd., trade name: ALCH), and 2.57915 g of terpineol (Japanese 萜Iso Chemical Co., Ltd. (sometimes abbreviated as "TPO"), 66.1969 g of isobornylcyclohexanol (Nippon Terpene Chemical Co., Ltd., sometimes abbreviated as "MTPH"), and mixed for 5 minutes. 1.2349 g of pure water was added and further kneaded for 5 minutes to prepare a composition 1 for passivation layer formation.

(Evaluation of Film Forming State of Passivation Layer) The prepared passivation layer forming composition 1 was printed on the entire surface of a single crystal p-type ruthenium substrate having a mirror surface shape by a screen printing method (156 mm square, thickness: 180) Μm, hereinafter referred to as "矽 substrate"). Then, the tantalum substrate to which the composition for forming the passivation layer 1 was applied was heated at 450 ° C for 5 minutes using a walking beam furnace (Wu-Wu Co., Ltd., a calcining furnace for heat treatment equipment for solar cells R&D). The liquid medium is transpiration and dried. Then, the tantalum substrate was heat-treated (calcined) at a temperature of 750 ° C for 10 minutes using a tube furnace (Koyo Thermo System Co., Ltd., MT12×43-A type), and then at room temperature (25 ° C). ) Place the cooling underneath.

The film formation state of the evaluation substrate obtained as described above was evaluated. For the evaluation substrate, an optical microscope (Olympus Co., Ltd., MX51) was used, and 10 points were randomly observed at a magnification of 50 times. In this case, those who are not confirmed to be cracks or cracks are considered to be good (A), and those who have confirmed cracks or cracks at one or more points are regarded as defective (B). The film formation state of the evaluation substrate obtained as described above was good.

(Measurement of Fixed Charge Density) The fixed charge density of the passivation layer formed on the substrate for evaluation was evaluated. A circular Al electrode of about 0.00025 cm ² was vapor-deposited on the surface of the evaluation substrate on which the passivation layer was formed. Using a transmission microscope (Hammam Photonics Co., Ltd., Phemos 200) with a probe, the probe was brought into needle contact with the vapor-deposited Al electrode, and the fixed charge density was calculated by the CV method. . The passivation layer has a fixed charge density of -2.1E + 12 (-2.1 × 10 ¹² ) cm ^-2 .

<Example 2> In Example 1, the blending amount was changed. Specifically, the content of each component was changed to 10.7815 g of tris(2-ethylhexanoate), the amount of ALCH was changed to 1.3015 g, the TPO was changed to 23.8978 g, and the MTPH was changed to 62.3181 g. The composition for forming a passivation layer 2 was prepared in the same manner as in Example 1 except that the amount was changed to 0.7933 g. Thereafter, evaluation of the film formation state of the passivation layer and measurement of the fixed charge density were carried out in the same manner as in Example 1.

<Example 3> In Example 1, the blending amount and material were changed. Specifically, tris(2-ethylhexanoate) ruthenium was changed to 8.0646 g, ALCH was changed to 1.1439 g, and ethoxy ruthenium (Beixing Chemical Industry Co., Ltd., structural formula: Nb (OC ₂ H ₅ )) ₅ , molecular weight: 318.2) was changed to 1.3872 g, TPO was changed to 22.5454 g, MTPH was changed to 60.3796 g, and pure water was changed to 1.0264 g, and the composition for forming a passivation layer was prepared in the same manner as in Example 1. Item 3. Thereafter, evaluation of the film formation state of the passivation layer and measurement of the fixed charge density were carried out in the same manner as in Example 1.

<Example 4> In Example 1, the blending amount and material were changed. Specifically, tris(2-ethylhexanoate) ruthenium was changed to 8.6887 g, ALCH was changed to 3.7254 g, and bismuth acid salt (Tama Chemical Industry Co., Ltd., trade name: citrate 40, sometimes A composition for forming a passivation layer was carried out in the same manner as in Example 1 except that the amount of "Si40" was changed to 0.3216 g, the TPO was changed to 24.8716 g, the MTPH was changed to 65.1844 g, and the pure water was changed to 1.2453 g. Matter 4. Thereafter, evaluation of the film formation state of the passivation layer and measurement of the fixed charge density were carried out in the same manner as in Example 1.

<Comparative Example 1> In Example 1, the blending amount and material were changed. Specifically, the cerium oxide was changed to 9.0168 g, the alumina was changed to 3.9165 g, the TPO was changed to 25.8568 g, the MTPH was changed to 66.8321 g, and the pure water was changed to 1.2764 g, otherwise the same as in Example 1. The composition for forming a passivation layer C1 was prepared. That is, the compound represented by the formula (I) was not used in Comparative Example 1. Thereafter, evaluation of the film formation state of the passivation layer and measurement of the fixed charge density were carried out in the same manner as in Example 1.

<Reference 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, the content of each component was changed in the same manner as in Example 1 except that the content of each component was changed to 11.6196 g, the TPO was changed to 22.9814 g, the MTPH was changed to 62.1949 g, and the pure water was changed to 1.5219 g. A composition R1 for forming a passivation layer was prepared. Thereafter, evaluation of the film formation state of the passivation layer and measurement of the fixed charge density were carried out in the same manner as in Example 1.

[Table 1]

The mixing ratio, the film formation state, and the fixed charge density evaluation results of the composition for forming a passivation layer which were carried out in Examples 1 to 4, Comparative Example 1, and Reference Example 1 are shown in Table 1. It is understood that the composition for forming a passivation layer formed in Examples 1 to 4 is excellent in a film formation state, and a passivation layer having a large negative fixed charge of -1E+12 cm ^-2 or more can be formed.

In the film formation of the evaluation substrate produced in Comparative Example 1, peeling occurred in the film formation, and the fixed charge density could not be calculated. It is shown that even if the metal oxide contained in the passivation layer of the present embodiment is directly provided, it cannot be a passivation layer and is in a peeled state; by imparting heat to the material contained in the present embodiment, it can be in a film-forming state. Good passivation layer.

Although the film formation state of the evaluation substrate prepared in Reference Example 1 was good, the fixed charge density was about 2 lower than that of the examples. It is shown that the passivation layer formed using the composition for forming a passivation layer containing the compound represented by the general formula (I) has excellent passivation characteristics.

The disclosure of Japanese Patent Application No. 2016-128085, filed on Jun. 28,,,,,,, All documents, patent applications, and technical specifications described in the specification are incorporated herein by reference to the same extent as the in.

1‧‧‧p-type semiconductor substrate
2‧‧‧n ⁺ type diffusion layer
3‧‧‧PSG (phosphorite glass) layer
4‧‧‧Anti-reflective film
5‧‧‧ Passivation layer
6‧‧‧Aluminum electrode paste, or aluminum electrode for backside collection obtained by heat treatment (calcination)
7‧‧‧Back surface output extraction electrode paste, or heat treatment (calcined)
8‧‧‧ Electrode paste for light-collecting surface collection or electrode for collecting surface of light-receiving surface obtained by heat treatment (calcination)
9‧‧‧ Light-receiving surface output extraction electrode obtained by removing the electrode paste from the smooth surface or heat-treating (calcining) it
10‧‧‧p ⁺ diffusion layer
11‧‧‧Aluminum electrode for back collector
L _a ‧‧‧ point diameter
L _b ‧‧‧ point interval
L _c ‧‧‧ line width
L _d ‧‧‧ line spacing
A‧‧‧ Part of the pattern of the passivation layer on the back
B‧‧‧ Part of the pattern of the passivation layer on the back side

(1) to (9) of FIG. 1 are cross-sectional views schematically showing an example of a method of manufacturing a solar cell element including a passivation layer. (10) to (18) of FIG. 2 are cross-sectional views schematically showing another example of a method of manufacturing a solar cell element including a passivation layer. (19) to (29) of FIG. 3 are cross-sectional views schematically showing another example of a method of manufacturing a solar cell element including a passivation layer. 4 is a schematic plan view showing an example of a light receiving surface of a solar cell element. FIG. 5 is a schematic plan view showing an example of a formation pattern of a passivation layer on the back surface. Fig. 6 is a schematic plan view showing another example of a pattern of formation of a passivation layer on the back surface. 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 enlarged portion A of Fig. 5; Fig. 10 is a schematic plan view showing an enlarged portion B of Fig. 5; Fig. 11 is a schematic plan view showing an example of a back surface of a solar cell element.

Claims (12)

A composition for forming a passivation layer comprising a compound represented by the following formula (I); Bi(OR ¹ ) _m (I) [R ¹ each independently represents an alkyl group, an aryl group or a fluorenyl group; m represents 3 Or 5]. The composition for forming a passivation layer according to claim 1, which further comprises water. The composition for forming a passivation layer according to claim 1 or 2, which comprises a hydrolyzate of the compound represented by the above formula (I). The composition for forming a passivation layer according to any one of claims 1 to 3, further comprising a compound represented by the following formula (III); M(OR ⁶ ) _l (III) [ In the formula (III), M represents at least one selected from the group consisting of Nb, Ta, VO, Y and Hf; R ⁶ each independently represents an alkyl group, an aryl group or a fluorenyl group; and 1 represents a valence of M ]. The composition for forming a passivation layer according to claim 4, wherein M in the compound represented by the formula (III) is Nb. The composition for forming a passivation layer according to claim 4, wherein the hydrolyzate of the compound represented by the above formula (III) is contained. A semiconductor substrate with a passivation layer, comprising: a semiconductor substrate; and a passivation layer provided on at least a portion of at least one of the semiconductor substrates, as in any one of claims 1 to 6 The heat treatment 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 claims 1 to 6 in at least a part of at least one surface of the semiconductor substrate And forming a composition layer; and subjecting the composition layer to heat treatment 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 6, 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 6; a step of heat-treating the composition layer to form a passivation layer; and the p-type layer and the n-type The step of arranging electrodes on at least one of the layers. The method for producing a solar cell element according to claim 10, wherein the step of forming a composition for forming a passivation layer to form a composition includes a screen printing method. A solar cell comprising: the solar cell element according to claim 9; and a wiring material disposed on the electrode of the solar cell element.