JPWO2015093608A1 - Semiconductor substrate manufacturing method, semiconductor substrate, solar cell element manufacturing method, and solar cell element - Google Patents

Abstract

The present invention relates to an n-type diffusion layer forming composition containing glass particles containing a donor element and a dispersion medium, and p-type diffusion layer formation containing glass particles containing an acceptor element and a dispersion medium in at least a part of a semiconductor substrate. Provided is a method for manufacturing a semiconductor substrate having a diffusion layer that includes a step of applying the composition to different regions, and a step of forming a p-type diffusion layer by forming an n-type diffusion layer by performing heat treatment. To do.

Description

  The present invention relates to a method for manufacturing a semiconductor substrate, a semiconductor substrate, a method for manufacturing a solar cell element, and a solar cell element.

  In a conventional solar cell element, a pn junction is formed by diffusing impurities of a conductivity type opposite to the conductivity type of the silicon substrate on the light receiving surface which is the surface of the silicon substrate on which sunlight is incident. Yes. Electrodes are formed on the light receiving surface of the silicon substrate and on the back surface opposite to the light receiving surface.

In said solar cell element, since the electrode is formed in the light-receiving surface, incidence | injection of sunlight is prevented by an electrode and there exists a problem that electric power generation efficiency falls. Therefore, a back contact type (back electrode type) solar cell in which an electrode is formed on the back surface without forming an electrode on the light receiving surface of the silicon substrate has been proposed. For example, U.S. Pat. No. 4,927,770 is a prior document relating to a method for manufacturing such a back contact solar cell. In US Pat. No. 4,927,770, after forming a dielectric layer such as SiO ₂ or SiNx on the back surface of a silicon substrate, a part of the dielectric layer is opened, and a dopant source compound is formed in the opening. The dopant is applied to diffuse the silicon substrate.

Further, in US Pat. No. 7,883,343, after forming a p-type diffusion layer (hereinafter also referred to as a p ⁺ layer) on the entire light-receiving surface and back surface of an n-type silicon substrate using BBr ₃ gas, A method is disclosed in which a resist is pattern coated on the back surface, a region other than the resist coating portion on the back surface and the light receiving surface are etched, and an n-type diffusion layer (hereinafter also referred to as an n ⁺ layer) is formed on the etched region and light receiving surface on the back surface Has been.

  In addition to the single-sided light receiving solar cell as described above, a double-sided light receiving solar cell that can receive light from both sides of the substrate is known. Such a solar cell is not only installed on a wall, etc., but can receive light from both sides, but in order to install it on a structure such as a roof, the back sheet has a reflective function, and the solar cell is exposed from the gap between the elements in the module. There has been proposed a type in which light transmitted through the back surface side of the battery element is reflected and light is also taken from the back surface side (see, for example, Japanese Patent Application Laid-Open No. 2012-195489). Thereby, it is supposed that the power generation efficiency of a solar cell will be improved.

As a method for generating a diffusion layer of a silicon substrate used for a double-sided light-receiving solar cell, first, a p ⁺ layer is collectively formed on both surfaces of a silicon substrate on which a texture structure is formed using BBr ₃ gas or the like. The p ⁺ layer generated by etching one side is removed. Next, after forming a mask layer on the surface where the p ⁺ layer is left, an n ⁺ layer is formed on the surface from which the p ⁺ layer has been removed by etching using POCl ₃ gas or the like. Thus, a method of forming the p ⁺ layer and the n ⁺ layer in separate steps is general (see, for example, Jpn. J. Appl. Phys. Vol. 42 (2003) pp. 5397-5404).

In the conventional method for manufacturing a solar cell element, the formation of the n ⁺ layer and the p ⁺ layer on the semiconductor substrate is performed in separate steps. This is because it is difficult to form the n ⁺ layer and the p ⁺ layer together for the following reason. The diffusion using a POCl _3, BBr _3, etc. of the gas, regioselectively doping (diffusion) it is difficult to, also in the case of using the conventional dopant material coating type instead of the gas, diffusion temperature ( In the case of 800 ° C. to 1000 ° C.), the dopant is easily volatilized, and it is difficult to do the site selective doping.

In the case where a p ⁺ layer and an n ⁺ layer are formed in a pattern on the back surface as proposed in US Pat. No. 4,927,770 and US Pat. No. 7,883,343. In general, many steps are required.

  In view of the above situation, an object of the present invention is to manufacture a semiconductor substrate having an n-type diffusion layer and a p-type diffusion layer at different locations on one semiconductor substrate by a simple method without requiring a complicated process. To do.

The present invention includes the following aspects.
<1> An n-type diffusion layer forming composition containing glass particles containing a donor element and a dispersion medium, and a p-type diffusion layer containing glass particles containing an acceptor element and a dispersion medium, at least partially on the semiconductor substrate Applying the composition to different areas,
Forming an n-type diffusion layer by performing heat treatment and forming a p-type diffusion layer;
A method for manufacturing a semiconductor substrate having a diffusion layer comprising:

<2> The method for manufacturing a semiconductor substrate having the diffusion layer according to <1>, wherein the n-type diffusion layer and the p-type diffusion layer are formed in a lump in the step of performing the heat treatment.

<3> The method for producing a semiconductor substrate having a diffusion layer according to <1> or <2>, wherein the donor element includes at least one selected from the group consisting of P (phosphorus) and Sb (antimony). .

<4> The glass particles containing the donor element include at least one donor element-containing material selected from the group consisting of P ₂ O ₃ , P ₂ O ₅ and Sb ₂ O ₃ , SiO ₂ , K ₂ O, At least one glass component material selected from the group consisting of Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ and MoO ₃ The manufacturing method of the semiconductor substrate which has a diffusion layer as described in any one of said <1>-<3> containing.

<5> Any one of <1> to <4>, wherein the acceptor element includes at least one element selected from the group consisting of B (boron), Al (aluminum), and Ga (gallium). The manufacturing method of the semiconductor substrate which has a diffusion layer as described in one.

<6> At least one acceptor element-containing material selected from the group consisting of B ₂ O ₃ , Al ₂ O ₃ and Ga ₂ O _3, wherein the glass particles containing the acceptor element, SiO ₂ , K ₂ O, Selected from the group consisting of Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, Tl ₂ O, V ₂ O ₅ , SnO, ZrO ₂ , WO ₃ , MoO ₃ and MnO. The manufacturing method of the semiconductor substrate which has a diffusion layer as described in any one of said <1>-<5> containing the at least 1 sort (s) of glass component substance.

<7> The semiconductor having the diffusion layer according to any one of <1> to <6>, further including a step of forming a passivation layer on at least one of the n-type diffusion layer and the p-type diffusion layer. A method for manufacturing a substrate.

<8> The diffusion layer according to any one of <1> to <7>, wherein the passivation layer contains at least one selected from the group consisting of silicon oxide, silicon nitride, and aluminum oxide. A method for manufacturing a semiconductor substrate.

<9> A semiconductor substrate having an n-type diffusion layer and a p-type diffusion layer obtained by the production method according to any one of <1> to <8>.

<10> A solar cell having a step of forming electrodes on an n-type diffusion layer and a p-type diffusion layer of a semiconductor substrate obtained by the manufacturing method according to any one of <1> to <8>. Device manufacturing method.

  <11> A solar cell element obtained by the production method according to <10>.

  According to the present invention, it is possible to manufacture a semiconductor substrate having an n-type diffusion layer and a p-type diffusion layer at different locations on one semiconductor substrate by a simple method without requiring a complicated process.

Fig.1 (a)-FIG.1 (f) are sectional drawings which show typically an example of the manufacturing method of the back contact type solar cell element concerning this invention. 2 (a) to 2 (f) are cross-sectional views schematically showing an example of a method for producing a double-sided light receiving solar cell element according to the present invention.

  In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes. . In the present specification, a numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, in the present specification, the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. Means.

  In the present specification, “content ratio” means the mass of each component when the total amount of the n-type diffusion layer forming composition or the p-type diffusion layer forming composition is 100% by mass unless otherwise specified. %. In addition, in the present specification, the term “layer” includes a configuration of a shape formed in part in addition to a configuration of a shape formed on the entire surface when observed as a plan view.

<Method for Manufacturing Semiconductor Substrate Having Diffusion Layer>
The method for producing a semiconductor substrate having a diffusion layer according to the present invention includes an n-type diffusion layer forming composition containing a glass particle containing a donor element and a dispersion medium, and glass particles containing an acceptor element in at least a part of the semiconductor substrate, and A step of applying a p-type diffusion layer-forming composition containing a dispersion medium to different regions, and a step of forming a p-type diffusion layer by forming an n-type diffusion layer by heat treatment. The method for producing a semiconductor substrate having a diffusion layer of the present invention may include other steps as necessary.

As described above, in the present invention, after the n-type diffusion layer forming composition and the p-type diffusion layer forming composition are applied to different locations on the semiconductor substrate, heat treatment is performed to perform the n-type diffusion layer forming composition and the p-type diffusion layer. A donor element and an acceptor element in the forming composition are diffused into the semiconductor substrate to form an n-type diffusion layer and a p-type diffusion layer.
By using the n-type diffusion layer forming composition and the p-type diffusion layer forming composition containing the dopant material, the composition layer (coating film) can be formed in a desired pattern in a desired region on the semiconductor substrate. In addition, by using donor element-containing glass particles and acceptor element-containing glass particles as dopant materials, it becomes difficult for the donor element and acceptor element to be volatilized, and the position of the p ⁺ layer and the n ⁺ layer is selected in a desired region on the semiconductor substrate. Can be formed. Furthermore, since the donor element and the acceptor element are respectively contained in the glass particles, and the donor element and the acceptor element are difficult to volatilize, the diffusion of the dopant to the region other than the region to which the diffusion layer forming composition is applied is suppressed, and the donor element Inhibition of diffusion and diffusion of acceptor elements from each other is suppressed, and the semiconductor substrate to which the n-type diffusion layer forming composition and the p-type diffusion layer forming composition are applied is heat-treated, whereby the donor element and the acceptor element are collectively treated. Can diffuse. In addition, since the donor element-containing glass particles and the acceptor element-containing glass particles are softened or melted when diffusing the donor element and the acceptor element into the semiconductor substrate, the heat-treated product tends to form a dense layer with few cracks. . Therefore, this heat-treated layer has high mask performance and can act as a mask layer as it is.
As described above, in the present invention, the etching process and the mask layer forming process which are essential in the conventional manufacturing method can be simplified, and the n ⁺ layer and the p ⁺ layer can be easily and collectively formed by heat treatment. It is.
In the conventional coating-type dopant material, pinholes and the like existed in the heat-treated product after the heat treatment, whereas in the present invention, the n-type diffusion layer forming composition and the p-type diffusion layer forming composition are used in the heat treatment. Since the semiconductor substrate is covered once softened, the occurrence of pinholes or the like in the heat-treated product is suppressed, and the mask performance of the heat-treated product tends to be improved.

  First, an n-type diffusion layer forming composition, a p-type diffusion layer forming composition and a semiconductor substrate used in the production method of the present invention will be described, and then a method for forming a diffusion layer on a semiconductor substrate using these will be described. .

(N-type diffusion layer forming composition)
The n-type diffusion layer forming composition according to the present invention contains at least glass particles containing a donor element (hereinafter also simply referred to as glass particles) and a dispersion medium. You may contain an additive as needed.
Here, the composition for forming an n-type diffusion layer is a composition that contains a donor element and is capable of forming an n-type diffusion layer in a semiconductor substrate by thermally diffusing the donor element after being applied to the semiconductor substrate. Say. By using the n-type diffusion layer forming composition containing the donor element in the glass particles, the n-type diffusion layer is formed in a desired portion of the semiconductor substrate, and the n-type diffusion layer is formed in an unnecessary region (for example, the side surface of the substrate). Can be prevented from being formed.

  Therefore, when the n-type diffusion layer forming composition according to the present invention is applied, patterning of the application region is possible and the process is simplified, unlike the gas phase reaction method widely used conventionally. In addition, when trying to form an n-type diffusion layer and a p-type diffusion layer in a lump using a highly volatile phosphorus compound such as phosphoric acid, diphosphorus pentoxide, and phosphate ester, other than the region to which the phosphorus compound is added Phosphorus is also diffused into the surface. This is because an acceptor element such as boron generally has a lower diffusion rate into a semiconductor substrate than phosphorus, and therefore, when an acceptor element is sufficiently diffused, a temperature higher than phosphorus diffusion (for example, 900 ° C.). This is because it is diffused at ˜950 ° C. and donor elements such as phosphorus are easily volatilized.

  The glass particles contained in the n-type diffusion layer forming composition according to the present invention are melted by heat treatment (firing) to form a glass layer on the n-type diffusion layer. However, even in the conventional gas phase reaction method and the method of applying a phosphate-containing solution or paste, a glass layer is formed on the n-type diffusion layer. In the same manner as in this method, it can be removed by etching. Therefore, the n-type diffusion layer forming composition according to the present invention does not generate unnecessary products and does not increase the number of manufacturing steps as compared with the conventional method.

  In addition, since the donor component in the glass particles is difficult to volatilize even during the heat treatment (baking) for diffusion, the formation of the n-type diffusion layer beyond the desired region of the semiconductor substrate due to the generation of the volatilizing gas is suppressed. . The reason for this is considered that the donor component is bonded to an element in the glass particle or is taken into the glass, and thus is difficult to volatilize.

  Furthermore, the n-type diffusion layer forming composition according to the present invention can form an n-type diffusion layer having a desired concentration at a desired site by adjusting the concentration of the donor element. A selective region having a high dopant concentration can be formed. On the other hand, it is generally difficult to selectively form a region having a high n-type dopant concentration by a gas phase reaction method, which is a general method for forming an n-type diffusion layer, or a method using a phosphate-containing solution. is there.

The glass particle containing the donor element used by this invention is demonstrated in detail.
A donor element is an element that can form an n-type diffusion layer by doping into a semiconductor substrate. As the donor element, a Group 15 element can be used, and examples thereof include P (phosphorus), Sb (antimony), Bi (bismuth), and As (arsenic). From the viewpoints of safety, ease of vitrification, etc., P or Sb is preferred.

The glass particle containing a donor element can be formed including, for example, a donor element-containing material and a glass component material. As the donor element-containing substance used to introduce the donor element to the glass particles, for _example, include _{P 2 O 3, P 2 O} 5, Sb 2 O 3, Bi 2 O 3 and _{As 2 O 3, P} 2 It is preferable to use at least one selected from the group consisting of O ₃ , P ₂ O ₅ and Sb ₂ O ₃ .

Examples of glass component materials include SiO ₂ , K ₂ O, Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, WO ₃ , MoO ₃ , _{MnO, La 2 O 3, Nb} 2 O 5, Ta 2 O 5, Y 2 O 3, TiO 2, ZrO 2, GeO 2, TeO 2, Lu 2 O 3 and the _like, SiO _{2, K} 2 _O, Use of at least one selected from the group consisting of Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ and MoO ₃ is used. Preferably, SiO ₂ , K ₂ O, Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ and MoO. More preferably, at least one selected from the group consisting of ₃ is used.

  Glass particles containing a donor element can control the melting temperature, softening point, glass transition point, chemical durability, and the like by adjusting the component ratio as necessary.

Specific examples of the glass particles containing a donor element include glass particles containing both a donor element-containing material and a glass component material. For example, P ₂ O ₅ —SiO ₂ (described in the order of donor element-containing substance-glass component substance, the same applies hereinafter) -containing glass particles, P ₂ O ₅ —K ₂ O-containing glass particles, P ₂ O ₅ —Na ₂ O containing glass _particles, P ₂ O 5 -Li ₂ O-containing glass _particles, P ₂ O 5 -BaO-containing glass _particles, P ₂ O 5 -SrO-containing glass _particles, P ₂ O 5 -CaO-containing glass _particles, P 2 _{O 5} -MgO-containing glass _particles, P ₂ O 5 -BeO containing glass _particles, P ₂ O 5 -ZnO-containing glass _particles, P ₂ O 5 -CdO containing glass _particles, P ₂ O 5 -PbO-containing glass _particles, P 2 _{O 5} -V ₂ O ₅ containing glass _particles, and P ₂ O 5 -SnO-containing glass _particles, P ₂ O 5 -GeO ₂ containing glass _particles, P ₂ O 5 -TeO ₂ containing a donor element-containing material of glass particles or the like Glass particles containing P ₂ O _5, and glass particles system containing _Sb 2 _{O 3} as a donor element-containing material and the like in place of the _P 2 _{O 5} glass particles containing _P 2 _{O 5} of the.
_{Incidentally, P 2 O 5 -Sb 2 O} 3 containing glass _particles, as in such P _{2 O} 5 _{-As 2} O ₃ containing glass particles, or glass particles containing two or more donor element-containing material.
In the above it has been illustrated composite glass particles comprising two _{components, P 2 O 5 -SiO 2 -V} 2 O 5, P 2 O 5 -SiO 2 -CaO , etc., may be glass particles comprising three or more components of the material.

  The content ratio of the glass component substance in the glass particles is preferably set in consideration of the melting temperature, the softening point, the glass transition point, and the chemical durability, and is generally 0.1% by mass to 95% by mass. It is preferable that it is 0.5 mass% or more and 90 mass% or less.

Further, as a glass component substance, from the group consisting of SiO ₂ , K ₂ O, Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, SnO, ZrO ₂ , and MoO _3. In the case of glass particles containing at least one selected, a reaction product with the semiconductor substrate does not remain as a residue during hydrofluoric acid treatment, which is preferable. In the case of glass particles containing vanadium oxide (V ₂ O ₅ ) as a glass component substance (for example, P ₂ O ₅ —V ₂ O ₅ containing glass particles), from the viewpoint of lowering the melting temperature, softening point, etc. The content ratio of V ₂ O ₅ is preferably 1% by mass or more and 50% by mass or less, and more preferably 3% by mass or more and 40% by mass or less.

  The softening point of the glass particles containing the donor element is preferably 200 ° C. to 1000 ° C., more preferably 300 ° C. to 900 ° C., from the viewpoints of diffusibility and dripping during heat treatment for diffusion. .

  The softening point of the glass particles can be measured by a differential thermal analysis (DTA) method. Specifically, a differential thermal analysis (DTA) apparatus is used, α-alumina is used as a reference, measurement is performed at a heating rate of about 10 K / min, and the second endothermic peak of the differential curve of the obtained DTA curve is defined as a softening point. can do. There is no restriction | limiting in particular in measurement atmosphere, It is preferable to measure in an atmosphere where glass particle is chemically stable.

  Examples of the shape of the glass particles containing the donor element include a substantially spherical shape, a flat shape, a block shape, a plate shape, and a scale shape. The shape of the glass particles containing the donor element is preferably substantially spherical, flat or plate-like from the viewpoints of coating properties on a semiconductor substrate and uniform diffusibility when an n-type diffusion layer forming composition is used.

The particle size of the glass particles containing the donor element is desirably 100 μm or less. When glass particles having a particle size of 100 μm or less are used, a smooth coating film can be easily obtained. Furthermore, the particle size of the glass particles is more desirably 50 μm or less, and further desirably 10 μm or less. In addition, the minimum in particular of the particle size of glass particle is not restrict | limited, It is preferable that it is 0.01 micrometer or more.
Here, the particle diameter of the glass particles containing the donor element represents a particle diameter D50% corresponding to 50% of the volume accumulation from the small diameter side in the particle size distribution, and can be measured by a laser scattering diffraction particle size distribution measuring apparatus or the like. .

Glass particles containing a donor element are produced, for example, by the following procedure.
First, raw materials (for example, the donor element-containing material and the glass component material) are weighed and filled in a crucible. Examples of the material for the crucible include platinum, platinum-rhodium, iridium, alumina, quartz, carbon, and the like. The material is appropriately selected in consideration of the melting temperature, atmosphere, reactivity with the molten material, mixing of impurities, and the like.
Next, it heats with the temperature according to a glass composition with an electric furnace, and is set as a melt. At this time, it is desirable to stir the melt uniformly.
The obtained melt is poured onto a zirconia substrate, a carbon substrate or the like to vitrify the melt. And glass is grind | pulverized and it is set as a powder form. A known apparatus such as a jet mill, a bead mill, or a ball mill can be applied to the pulverization.

The content ratio of the glass particles containing the donor element in the n-type diffusion layer forming composition is determined in consideration of the coating property, the diffusibility of the donor element, and the like. In general, the content ratio of the glass particles in the n-type diffusion layer forming composition is preferably 0.1% by mass or more and 95% by mass or less, more preferably 1% by mass or more and 90% by mass or less, The content is more preferably 1.5% by mass or more and 85% by mass or less, and particularly preferably 2% by mass or more and 80% by mass or less.
The content ratio of the inorganic compound component in the total solid content of the n-type diffusion layer forming composition is preferably 40% by mass or more, more preferably 60% by mass or more, and 70% by mass or more. Is more preferable, and 80% by mass or more is particularly preferable.
The content ratio of the glass particles containing the donor element in the inorganic compound component is preferably 50% by mass or more, more preferably 75% by mass or more, and still more preferably 85% by mass or more. 90 mass% or more is especially preferable.

Next, the dispersion medium will be described.
The dispersion medium is a medium in which the glass particles are dispersed in the n-type diffusion layer forming composition. Specifically, a binder and a solvent are employed as the dispersion medium.

Examples of binders include polyvinyl alcohol, polyacrylamide resin, polyvinylamide resin, polyvinylpyrrolidone resin, polyethylene oxide resin, polysulfone resin, acrylamide alkyl sulfone resin, cellulose ether, carboxymethyl cellulose, hydroxyethyl cellulose, ethyl cellulose and other cellulose derivatives, gelatin, gelatin derivatives , Starch, starch derivative, sodium alginate compound, xanthan, guar gum, guar gum derivative, scleroglucan, scleroglucan derivative, tragacanth, tragacanth derivative, dextrin, dextrin derivative, (meth) acrylic acid resin, (meth) acrylic acid ester resin (For example, alkyl (meth) acrylate resin and dimethylaminoethyl (meth) acrylate Rate resin), butadiene resins, styrene resins, butyral resins, copolymers thereof, may appropriately select a siloxane resin or the like. These are used singly or in combination of two or more.
Here, (meth) acrylic acid means acrylic acid or methacrylic acid, and (meth) acrylate means acrylate or methacrylate.

  Among these, from the viewpoints of degradability and prevention of dripping at the time of screen printing, the binder preferably includes an acrylic acid resin, a butyral resin, or a cellulose derivative, and preferably includes at least a cellulose derivative. Examples of the cellulose derivative include ethyl cellulose, nitrocellulose, acetyl cellulose, carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, and hydroxyethyl cellulose. Among these, ethyl cellulose is preferably used. A binder is used individually by 1 type or in combination of 2 or more types.

  The molecular weight of the binder is not particularly limited, and it is desirable to adjust appropriately in view of the desired viscosity as the n-type diffusion layer forming composition. When the n-type diffusion layer forming composition contains a binder, the binder content in the n-type diffusion layer forming composition is preferably 0.5% by mass or more and 30% by mass or less, and preferably 3% by mass or more and 25% by mass. % Or less, more preferably 3% by mass or more and 20% by mass or less.

Examples of the solvent include acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl isopropyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl n-hexyl ketone, diethyl ketone, and dipropyl. Ketone solvents such as ketone, diisobutyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diethyl ether, methyl ethyl ether, methyl-n-propyl ether, diisopropyl ether, Tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol -N-propyl ether, ethylene glycol dibutyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl-n-propyl ether, diethylene glycol methyl n-butyl ether, diethylene glycol di-n-propyl ether, Diethylene glycol di-n-butyl ether, diethylene glycol methyl-n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl n-butyl ether, triethylene glycol di-n-butyl Ether, triethylene glycol methyl-n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol methyl n-butyl ether, tetraethylene glycol di-n-butyl ether, tetraethylene Glycol methyl-n-hexyl ether, tetraethylene glycol di-n-butyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether Dipropylene glycol methyl ethyl Ether, dipropylene glycol methyl-n-butyl ether, dipropylene glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether , Tripropylene glycol methyl ethyl ether, tripropylene glycol methyl n-butyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol methyl n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetrapropylene glycol Methyl ethyl ether, tetrapropylene glycol methyl-n- Ether solvents such as chill ether, tetrapropylene glycol di-n-butyl ether, tetrapropylene glycol methyl n-hexyl ether, tetrapropylene glycol di-n-butyl ether, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n acetate -Butyl, isobutyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 2- (2-butoxyethoxy) acetate Ethyl, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, acetic acid Propylene glycol methyl ether, dipropylene glycol ethyl ether acetate, diacetic acid glycol, methoxytriethylene glycol 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 methyl ether acetate, propylene glycol Ethyl ether acetate, propylene glycol propyl ether acetate, γ-butyrolactone, γ-valerolactone, etc. Tellurium solvent, acetonitrile, N-methylpyrrolidinone, N-ethylpyrrolidinone, N-propylpyrrolidinone, N-butylpyrrolidinone, N-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl Aprotic polar solvents such as sulfoxide, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, n-pentanol, isopentanol, 2-methylbutanol, sec- Pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n-octanol, 2 -Ethylhexanol, sec-octanol, n-nonyl alcohol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexanol, benzyl alcohol , Isobornylcyclohexanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol and other alcohol solvents, ethylene glycol monomethyl ether, ethylene glycol mono Ethyl ether (cellosolve), ethylene glycol monophenyl ether, diethylene glycol monomethyl Ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono Glycol monoether solvents such as ethyl ether and tripropylene glycol monomethyl ether, terpene solvents such as α-terpinene, terpineol, myrcene, alloocimene, limonene, dipentene, α-pinene, β-pinene, carvone, osymene, and ferrandolene, isovol Nylcyclohexanol, isobornylphenol, 1-isopropyl-4-methyl-bicyclo [2 2.2] oct-5-ene-2,3-dicarboxylic anhydride, p- maintenance alkenyl phenols and water. These are used singly or in combination of two or more.

  Among these, from the viewpoint of applicability to a semiconductor substrate, the dispersion medium is preferably water, alcohol solvent, glycol monoether solvent, or terpene solvent, water, alcohol, cellosolve, terpineol, diethylene glycol mono-n-butyl ether, Or, diethylene glycol mono-n-butyl ether acetate is more preferable, and water, alcohol, terpineol or cellosolve is more preferable.

  The content ratio of the dispersion medium in the n-type diffusion layer forming composition is determined in consideration of coating properties, donor element concentration, and the like. The viscosity of the n-type diffusion layer forming composition is preferably 10 mPa · s or more and 1000000 mPa · s or less, and more preferably 50 mPa · s or more and 500000 mPa · s or less in consideration of applicability.

Furthermore, the n-type diffusion layer forming composition may contain other additives. Examples of other additives include metals that easily react with the glass particles.
The n-type diffusion layer forming composition is applied on a semiconductor substrate and heat-treated at a high temperature to form an n-type diffusion layer, and glass is formed on the substrate surface at that time. Although this glass is removed by dipping in an acid such as hydrofluoric acid, some glass is difficult to remove depending on the type of glass. In that case, by adding a metal such as Ag, Mn, Cu, Fe, Zn, or Si to the n-type diffusion layer forming composition, the glass tends to be easily removed by acid cleaning. Among these, it is preferable to use at least one selected from the group consisting of Ag, Si, Cu, Fe, Zn and Mn, and to use at least one selected from the group consisting of Ag, Si and Zn. Is more preferable, and it is more preferable to use Ag.

  The content ratio of the metal is desirably adjusted as appropriate depending on the type of glass, the type of the metal, and the like, and is generally preferably 0.01% by mass to 10% by mass with respect to the glass particles.

(P-type diffusion layer forming composition)
The p-type diffusion layer forming composition contains at least glass particles containing an acceptor element (hereinafter also simply referred to as glass particles) and a dispersion medium, and further includes other additives in consideration of coating properties and the like. You may contain as needed.
Here, the p-type diffusion layer forming composition is a composition that contains an acceptor element and is capable of forming a p-type diffusion layer in a semiconductor substrate by thermally diffusing the acceptor element after being applied to the semiconductor substrate. Say. By using a p-type diffusion layer forming composition containing an acceptor element in glass particles, a p-type diffusion layer is formed in a desired portion of a semiconductor substrate and a p-type diffusion layer is prevented from being formed in an unnecessary region. it can.

  In addition, since the acceptor element in the glass particles is difficult to be volatilized even during the heat treatment (baking) for diffusion, the formation of the p-type diffusion layer beyond the desired region due to the generation of the volatilizing gas is suppressed. This is considered to be because the acceptor element is bonded to the element in the glass particle or is taken into the glass, so that it is difficult to volatilize.

  Further, the p-type diffusion layer forming composition according to the present invention can form a p-type diffusion layer having a desired concentration at a desired site by adjusting the concentration of the acceptor element. A selective region having a high dopant concentration can be formed. On the other hand, it is generally difficult to selectively form a region having a high p-type dopant concentration by a gas phase reaction method, which is a general method for forming a p-type diffusion layer, or a method using a phosphate-containing solution. is there.

The glass particles containing the acceptor element used in the present invention will be described in detail.
An acceptor element is an element that can form a p-type diffusion layer by doping into a semiconductor substrate. As the acceptor element, a Group 13 element can be used, and examples thereof include B (boron), Al (aluminum), and Ga (gallium). From the viewpoint of easiness of vitrification, B or Ga is preferable.

The glass particle containing an acceptor element can be formed including, for example, an acceptor element-containing substance and a glass component substance. Examples of the acceptor element-containing material used for introducing the acceptor element into the glass particles include B ₂ O ₃ , Al ₂ O ₃ , and Ga ₂ O ₃ , and B ₂ O ₃ , Al ₂ O _3, and Ga are included. It is preferable to use at least one selected from the group consisting of ₂ O ₃ .

Examples of glass component materials include SiO ₂ , K ₂ O, Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, Tl ₂ O, V ₂ O ₅ , SnO, and ZrO _{2. , WO 3, MoO 3, MnO} , La 2 O 3, Nb 2 O 5, Ta 2 O 5, Y 2 O 3, TiO 2, GeO 2, TeO 2, Lu 2 O 3 and the like, _SiO 2, From K ₂ O, Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, Tl ₂ O, V ₂ O ₅ , SnO, ZrO ₂ , WO ₃ , MoO ₃ and MnO It is preferable to use at least one selected from the group consisting of:

  Moreover, the glass particle containing an acceptor element can control a melting temperature, a softening point, a glass transition point, chemical durability, etc. by adjusting a component ratio as needed.

Specific examples of the glass particles containing an acceptor element include glass particles containing both an acceptor element-containing substance and a glass component substance. For example, B ₂ O ₃ —SiO ₂ (described in the order of acceptor element-containing substance-glass component substance, the same applies hereinafter) containing glass particles, B ₂ O ₃ —ZnO containing glass particles, B ₂ O ₃ —PbO containing glass particles, Al ₂ O ₃ —SiO ₂ containing glass particles, B ₂ O ₃ —Al ₂ O ₃ containing glass particles, Ga ₂ O ₃ —SiO ₂ containing glass particles, Ga ₂ O ₃ —B ₂ O ₃ containing glass particles, B ₂ Examples thereof include glass particles such as O ₃ alone-containing glass particles.

In the above has been illustrated composite glass containing one-component glass and _2-component, may be three or more types of composite glass particles optionally B ₂ O 3 -SiO ₂ -Na ₂ O or the like. _Further, as such _{Al 2 O 3 -B 2 O 3} , or glass particles comprising two or more acceptor element-containing material.

  The content ratio of the glass component substance in the glass particles is preferably set in consideration of the melting temperature, the softening point, the glass transition point, and the chemical durability, and is generally 0.1% by mass to 95% by mass. It is preferable that it is 0.5 mass% or more and 90 mass% or less.

Specifically, in the case of glass particles containing B ₂ O ₃ —SiO ₂ —CaO, the content ratio of CaO is preferably 1% by mass to 30% by mass, and preferably 5% by mass to 20% by mass. It is more preferable that

Further, as a glass component substance, from the group consisting of SiO ₂ , K ₂ O, Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, SnO, ZrO ₂ , and MoO _3. In the case of glass particles containing at least one selected, a reaction product with the semiconductor substrate does not remain as a residue during hydrofluoric acid treatment, which is preferable. In the case of glass particles containing vanadium oxide (V ₂ O ₅ ) as a glass component substance (for example, P ₂ O ₅ —V ₂ O ₅ containing glass particles), from the viewpoint of lowering the melting temperature, softening point, etc. The content ratio of V ₂ O ₅ is preferably 1% by mass or more and 50% by mass or less, and more preferably 3% by mass or more and 40% by mass or less.

  The softening point of the glass particles containing the acceptor element is preferably 200 ° C. to 1000 ° C., more preferably 300 ° C. to 950 ° C., from the viewpoints of diffusibility during heat treatment for diffusion, dripping, and the like. .

  The softening point of the glass particles can be measured by a differential thermal analysis (DTA) method. Specifically, a differential thermal analysis (DTA) apparatus is used, α-alumina is used as a reference, measurement is performed at a heating rate of about 10 K / min, and the second endothermic peak of the differential curve of the obtained DTA curve is defined as a softening point. can do. There is no restriction | limiting in particular in measurement atmosphere, It is preferable to measure in an atmosphere where glass particle is chemically stable.

  Examples of the shape of the glass particles containing the acceptor element include a substantially spherical shape, a flat shape, a block shape, a plate shape, and a scale shape. The glass particles containing the acceptor element preferably have a substantially spherical shape, a flat shape, or a plate shape from the viewpoints of applicability to a semiconductor substrate and uniform diffusibility when a p-type diffusion layer forming composition is used.

The average particle size of the glass particles containing the acceptor element is desirably 100 μm or less. When glass particles having an average particle size of 100 μm or less are used, a smooth coating film is easily obtained. Further, the average particle size of the glass particles is more preferably 50 μm or less, and further preferably 10 μm or less. In addition, the minimum in particular of the particle size of glass particle is not restrict | limited, It is preferable that it is 0.01 micrometer or more.
Here, the average particle diameter of the glass represents a particle diameter D50% corresponding to 50% of volume accumulation from the small diameter side in the particle size distribution, and can be measured by a laser scattering diffraction particle size distribution measuring apparatus or the like.

Glass particles containing an acceptor element are produced, for example, by the following procedure.
First, raw materials (for example, the acceptor element-containing material and the glass component material) are weighed and filled in a crucible. Examples of the material for the crucible include platinum, platinum-rhodium, iridium, alumina, quartz, carbon, and the like. The material is appropriately selected in consideration of the melting temperature, atmosphere, reactivity with the molten material, mixing of impurities, and the like.
Next, it heats with the temperature according to a glass composition with an electric furnace, and is set as a melt. At this time, it is desirable to stir the melt uniformly.
The obtained melt is poured onto a zirconia substrate, a carbon substrate or the like to vitrify the melt. And glass is grind | pulverized and it is set as a powder form. A known apparatus such as a jet mill, a bead mill, or a ball mill can be applied to the pulverization.

The content ratio of the glass particles containing the acceptor element in the p-type diffusion layer forming composition is determined in consideration of applicability, diffusibility of the acceptor element, and the like. In general, the content ratio of the glass particles in the p-type diffusion layer forming composition is preferably 0.1% by mass or more and 95% by mass or less, more preferably 1% by mass or more and 90% by mass or less, The content is more preferably 1.5% by mass or more and 85% by mass or less, and particularly preferably 2% by mass or more and 80% by mass or less.
The content ratio of the inorganic compound component in the total solid content of the p-type diffusion layer forming composition is preferably 40% by mass or more, more preferably 60% by mass or more, and 70% by mass or more. Is more preferable, and 80% by mass or more is particularly preferable.
The content ratio of the glass particles containing the acceptor element in the inorganic compound component is preferably 50% by mass or more, more preferably 75% by mass or more, and still more preferably 85% by mass or more. 90 mass% or more is especially preferable.

Next, the dispersion medium will be described.
The dispersion medium is a medium in which the glass particles are dispersed in the p-type diffusion layer forming composition. Specifically, a binder and a solvent are employed as the dispersion medium.

Examples of binders include polyvinyl alcohol, polyacrylamide resin, polyvinylamide resin, polyvinylpyrrolidone resin, polyethylene oxide resin, polysulfone resin, acrylamide alkyl sulfone resin, cellulose ether, carboxymethyl cellulose, hydroxyethyl cellulose, ethyl cellulose and other cellulose derivatives, gelatin, gelatin derivatives , Starch, starch derivatives, sodium alginate, xanthan, guar gum, guar gum derivative, scleroglucan, scleroglucan derivative, tragacanth, tragacanth derivative, dextrin, dextrin derivative, (meth) acrylic ester resin, (meth) acrylic ester Resins (eg, alkyl (meth) acrylate resins and dimethylaminoethyl (meth) Acrylate resin), butadiene resins, styrene resins, butyral resins, copolymers thereof, siloxane resins. These are used singly or in combination of two or more.
Here, (meth) acrylic acid means acrylic acid or methacrylic acid, and (meth) acrylate means acrylate or methacrylate.

  Among these, from the viewpoints of degradability and prevention of dripping at the time of screen printing, the binder preferably includes an acrylic acid resin, a butyral resin, or a cellulose derivative, and preferably includes at least a cellulose derivative. Examples of the cellulose derivative include ethyl cellulose, nitrocellulose, acetyl cellulose, carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, and hydroxyethyl cellulose. Among these, ethyl cellulose is preferably used. These are used singly or in combination of two or more.

  The molecular weight of the binder is not particularly limited, and it is desirable to adjust appropriately in view of the desired viscosity as the p-type diffusion layer forming composition. When the p-type diffusion layer forming composition contains a binder, the binder content in the p-type diffusion layer forming composition is preferably 0.5% by mass or more and 30% by mass or less, and preferably 3% by mass or more and 25% by mass. % Or less, more preferably 3% by mass or more and 20% by mass or less.

  Examples of the solvent include acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl isopropyl ketone, methyl n-butyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl n-hexyl ketone, diethyl ketone, and dipropyl. Ketone solvents such as ketone, diisobutyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diethyl ether, methyl ethyl ether, methyl-n-propyl ether, diisopropyl ether, Tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol -N-propyl ether, ethylene glycol dibutyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl-n-propyl ether, diethylene glycol methyl n-butyl ether, diethylene glycol di-n-propyl ether, Diethylene glycol di-n-butyl ether, diethylene glycol methyl-n-hexyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl n-butyl ether, triethylene glycol di-n-butyl Ether, triethylene glycol methyl-n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol methyl n-butyl ether, tetraethylene glycol di-n-butyl ether, tetraethylene Glycol methyl-n-hexyl ether, tetraethylene glycol di-n-butyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol di-n-propyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether Dipropylene glycol methyl ethyl Ether, dipropylene glycol methyl-n-butyl ether, dipropylene glycol di-n-propyl ether, dipropylene glycol di-n-butyl ether, dipropylene glycol methyl-n-hexyl ether, tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether , Tripropylene glycol methyl ethyl ether, tripropylene glycol methyl n-butyl ether, tripropylene glycol di-n-butyl ether, tripropylene glycol methyl n-hexyl ether, tetrapropylene glycol dimethyl ether, tetrapropylene glycol diethyl ether, tetrapropylene glycol Methyl ethyl ether, tetrapropylene glycol methyl-n- Ether solvents such as chill ether, tetrapropylene glycol di-n-butyl ether, tetrapropylene glycol methyl n-hexyl ether, tetrapropylene glycol di-n-butyl ether, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n acetate -Butyl, isobutyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 2- (2-butoxyethoxy) acetate Ethyl, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, acetic acid Propylene glycol methyl ether, dipropylene glycol ethyl ether acetate, diacetic acid glycol, methoxytriethylene glycol 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 methyl ether acetate, propylene glycol Ethyl ether acetate, propylene glycol propyl ether acetate, γ-butyrolactone, γ-valerolactone, etc. Tellurium solvent, acetonitrile, N-methylpyrrolidinone, N-ethylpyrrolidinone, N-propylpyrrolidinone, N-butylpyrrolidinone, N-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl Aprotic polar solvents such as sulfoxide, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, n-pentanol, isopentanol, 2-methylbutanol, sec- Pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n-octanol, 2 -Ethylhexanol, sec-octanol, n-nonyl alcohol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexanol, benzyl alcohol , Isobornylcyclohexanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol and other alcohol solvents, ethylene glycol monomethyl ether, ethylene glycol mono Ethyl ether (cellosolve), ethylene glycol monophenyl ether, diethylene glycol monomethyl Ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono Glycol monoether solvents such as ethyl ether and tripropylene glycol monomethyl ether, terpene solvents such as α-terpinene, terpineol, myrcene, alloocimene, limonene, dipentene, α-pinene, β-pinene, carvone, osymene, and ferrandolene, isovol Nylcyclohexanol, isobornylphenol, 1-isopropyl-4-methyl-bicyclo [2 2.2] oct-5-ene-2,3-dicarboxylic anhydride, p- maintenance alkenyl phenols and water. These are used singly or in combination of two or more.

  Among these, from the viewpoint of applicability to a semiconductor substrate, the dispersion medium is preferably water, alcohol solvent, glycol monoether solvent, or terpene solvent, water, alcohol, cellosolve, terpineol, diethylene glycol mono-n-butyl ether, Or, diethylene glycol mono-n-butyl ether acetate is more preferable, and water, alcohol, terpineol or cellosolve is more preferable.

  The content ratio of the dispersion medium in the p-type diffusion layer forming composition is determined in consideration of applicability, acceptor element concentration, and the like. The viscosity of the p-type diffusion layer forming composition is preferably 10 mPa · s or more and 1000000 mPa · s or less, and more preferably 50 mPa · s or more and 500000 mPa · s or less in consideration of applicability.

Furthermore, the p-type diffusion layer forming composition may contain other additives. Examples of other additives include metals that easily react with the glass particles.
The p-type diffusion layer forming composition is applied on a semiconductor substrate and heat-treated at a high temperature to form a p-type diffusion layer. At that time, glass is formed on the surface of the substrate. Although this glass is removed by dipping in an acid such as hydrofluoric acid, some glass is difficult to remove depending on the type of glass. In that case, by adding a metal such as Ag, Mn, Cu, Fe, Zn, or Si to the p-type diffusion layer forming composition, the glass tends to be easily removed by acid cleaning. Among these, it is preferable to use at least one selected from the group consisting of Ag, Si, Cu, Fe, Zn and Mn, and to use at least one selected from the group consisting of Ag, Si and Zn. Is more preferable, and it is more preferable to use Ag.

  The content ratio of the metal is desirably adjusted as appropriate depending on the type of glass, the type of the metal, and the like, and is generally preferably 0.01% by mass to 10% by mass with respect to the glass particles.

(Semiconductor substrate)
The semiconductor substrate is not particularly limited, and a normal substrate can be applied. Silicon substrate, gallium phosphide substrate, gallium nitride substrate, diamond substrate, aluminum nitride substrate, indium nitride substrate, gallium arsenide substrate, germanium selenide substrate, zinc telluride substrate, cadmium telluride substrate, cadmium sulfide substrate, Examples thereof include a gallium arsenide substrate, an indium phosphide substrate, a gallium nitride substrate, a silicon carbide substrate, a silicon germanium substrate, and a copper indium selenium substrate. When used for a solar cell element, the semiconductor element is preferably a silicon substrate, a germanium substrate, or a silicon carbide substrate, and more preferably a silicon substrate.

(Semiconductor substrate manufacturing method)
In the method for producing a semiconductor substrate of the present invention, an n-type diffusion layer forming composition and a p-type diffusion layer forming composition are applied to at least some different regions on the semiconductor substrate, and then an acceptor element and a donor element are subjected to heat treatment. Are diffused into the semiconductor substrate to form a p-type diffusion layer and an n-type diffusion layer.
In the step of applying the n-type diffusion layer forming composition and the p-type diffusion layer forming composition, the order of applying the n-type diffusion layer forming composition and the p-type diffusion layer forming composition is not limited. For example, the p-type diffusion layer forming composition may be applied after the n-type diffusion layer forming composition is applied, or the n-type diffusion layer forming composition may be applied after the p-type diffusion layer forming composition is applied. Alternatively, the n-type diffusion layer forming composition and the p-type diffusion layer forming composition may be applied together.

  The method for manufacturing a semiconductor substrate of the present invention may further include a step of forming a passivation layer on the p-type diffusion layer and the n-type diffusion layer. The passivation layer preferably contains at least one selected from silicon oxide, silicon nitride, and aluminum oxide.

  Below, an example of the manufacturing method of the semiconductor substrate of this invention is demonstrated in the manufacturing method of a back contact type solar cell element. In this method of manufacturing a back contact solar cell element, a method using a silicon substrate as the semiconductor substrate will be described.

  In the method of manufacturing a back contact solar cell element, first, a damaged layer on the surface of a silicon substrate, for example, an n-type silicon substrate, is etched using an acidic or alkaline solution to remove the damaged layer. For example, the damage layer on the surface of the silicon substrate can be removed by immersing the silicon substrate in a high-concentration NaOH aqueous solution of 30% by mass or more heated to about 80 ° C. for 5 minutes or more.

  Next, only the light receiving surface side of the silicon substrate is etched using an alkaline solution to form a fine uneven structure called a texture structure on the light receiving surface. The texture structure is formed, for example, by immersing a silicon substrate provided with a protective layer in advance at a location where it is not desired to form the texture structure, in a solution of about 80 ° C. containing potassium hydroxide and isopropyl alcohol (IPA). be able to.

  In order to form a texture structure only on one side of the silicon substrate, a water-resistant resist is applied to the other side of the silicon substrate, and the entire silicon substrate is immersed in an aqueous potassium hydroxide solution, or a silicon substrate is used using a floating device or the like. It can be formed by immersing only one side of this in an aqueous potassium hydroxide solution. When using a resist, the resist is removed after the texture structure forming step.

  Next, after applying the n-type diffusion layer forming composition and the p-type diffusion layer forming composition in a pattern on the surface on the back side opposite to the light receiving surface of the silicon substrate, respectively, the silicon substrate is subjected to a heat treatment. An n-type diffusion layer and a p-type diffusion layer are collectively formed on the back surface of the substrate.

A method for applying the p-type diffusion layer forming composition and the n-type diffusion layer forming composition is not particularly limited, and a method usually used in this technical field can be used. For the application of the p-type and n-type diffusion layer forming compositions, printing methods such as screen printing methods and gravure printing methods, spin coating methods, brush coating methods, spray methods, doctor blade methods, roll coating methods, ink jet methods, etc. A method that allows patterning, such as a printing method, a spray method, and an ink jet method, is preferable.
There are no particular restrictions on the amount of p-type diffusion layer forming composition and n-type diffusion layer forming composition applied to the substrate. For example, it is possible to 0.01g ^{/ m 2} ~100g ^/ m 2 as the amount of glass ^particles, is preferably ^{0.1g / m 2 ~10g / m 2} .

After applying the p-type diffusion layer forming composition and the n-type diffusion layer forming composition on the silicon substrate, a heating step for removing at least a part of the dispersion medium may be provided if desired. In the heating step, for example, at least a part of the solvent can be volatilized by heat treatment at 100 ° C. to 300 ° C. For example, at least a part of the binder can be removed by heat treatment at 200 ° C. to 700 ° C.
The processing time in the heating process for removing at least a part of the dispersion medium is about 1 to 10 minutes when using a hot plate, and about 10 to 30 minutes when using a dryer or the like. The drying conditions depend on the dispersion medium composition of the n-type diffusion layer forming composition or the p-type diffusion layer forming composition, and are not particularly limited to the above conditions in the present invention.

  The gas atmosphere used for the heat treatment (thermal diffusion) for forming the p-type diffusion layer and the n-type diffusion layer is not particularly limited, and in a mixed gas atmosphere such as nitrogen, oxygen, argon, helium, xenon, neon, krypton, etc. Preferably there is.

  The temperature of the heat treatment (thermal diffusion) for forming the p-type diffusion layer and the n-type diffusion layer is preferably 800 ° C. or higher and 1100 ° C. or lower, more preferably 850 ° C. or higher and 1100 ° C. or lower, 900 ° C. The temperature is more preferably 1100 ° C. or lower.

  Since the glass layer remains on the silicon substrate on which the p-type diffusion layer and the n-type diffusion layer are formed by the above process, it is preferable to remove the glass layer by etching. As the etching, a known method such as a method of immersing in an acid such as hydrofluoric acid or a method of immersing in an alkali such as caustic soda can be applied.

  Next, an antireflection layer is formed on the light receiving surface (surface). Here, as the antireflection layer, for example, a nitride layer formed by a plasma CVD method can be used. Moreover, it is preferable to form a passivation layer on the back side. Examples of the passivation layer include a thermal oxide layer, an aluminum oxide layer, a SiNx layer, an amorphous silicon layer, and the like, and can be formed by a vapor deposition method or a coating method. In the case of a SiNx layer, it can also serve as passivation and antireflection. The passivation layer may be a single layer structure, or a multi-layer structure such as a two-layer structure or a three-layer structure. For example, a thermal oxide layer and a SiNx layer are passivated on a silicon substrate in this order. Also good.

Next, an electrode is formed on the back surface of the silicon substrate. For the formation of the electrode, a method usually used in the technical field can be used without particular limitation.
For example, a metal paste for a surface electrode including metal particles and glass particles is applied on the diffusion layer forming region so as to have a desired shape, and this is heat-treated (fired) to thereby form a p-type diffusion layer and an n-type diffusion layer. A surface electrode can be formed in the electrode forming region. As the surface electrode metal paste, for example, a silver paste or the like usually used in the technical field can be used.

  Next, another example of the method for producing a semiconductor substrate of the present invention will be described in the method for producing a double-sided light receiving solar cell element. In this method for manufacturing a double-sided light receiving solar cell element, a method using a silicon substrate as a semiconductor substrate will be described.

  In the method for manufacturing a double-sided light receiving solar cell element, first, a damaged layer on the surface of a silicon substrate, for example, an n-type silicon substrate, is etched using an acidic or alkaline solution to remove the damaged layer. For example, the damage layer on the surface of the silicon substrate can be removed by immersing the silicon substrate in a high concentration NaOH aqueous solution of 30% by mass or more heated to about 80 ° C. for 5 minutes or more.

  Next, both sides of the silicon substrate are etched using an alkaline solution to form fine concavo-convex structures called texture structures on both sides. The texture structure can be formed, for example, by immersing the silicon substrate in a liquid at about 80 ° C. containing potassium hydroxide and isopropyl alcohol (IPA).

  Next, a p-type diffusion layer forming composition is applied to one surface of the n-type silicon substrate, and an n-type diffusion layer forming composition is applied to the other surface entirely or in a pattern, followed by heat treatment. The n-type diffusion layer and the p-type diffusion layer are collectively formed on both surfaces of the silicon substrate.

A method for applying the p-type diffusion layer forming composition and the n-type diffusion layer forming composition is not particularly limited, and a method usually used in this technical field can be used. For the application of the p-type and n-type diffusion layer forming compositions, printing methods such as screen printing methods and gravure printing methods, spin coating methods, brush coating methods, spray methods, doctor blade methods, roll coating methods, ink jet methods, etc. A method that allows patterning, such as a printing method, a spray method, and an ink jet method, is preferable.
There are no particular restrictions on the amount of the p-type diffusion layer forming composition and the n-type diffusion layer forming composition applied to the substrate. For example, it is possible to 0.01g ^{/ m 2} ~100g ^/ m 2 as the amount of glass ^particles, is preferably ^{0.1g / m 2 ~10g / m 2} .

After applying the p-type diffusion layer forming composition and the n-type diffusion layer forming composition on the silicon substrate, a heating step for removing at least a part of the dispersion medium may be provided if desired. In the heating step, for example, at least a part of the solvent can be volatilized by heat treatment at 100 ° C. to 300 ° C. For example, at least a part of the binder can be removed by heat treatment at 200 ° C. to 700 ° C.
The processing time in the heating process for removing at least a part of the dispersion medium is about 1 to 10 minutes when using a hot plate, and about 10 to 30 minutes when using a dryer or the like. The drying conditions depend on the dispersion medium composition of the n-type diffusion layer forming composition and are not particularly limited to the above conditions in the present invention.

  The gas atmosphere used for the heat treatment (thermal diffusion) for forming the p-type diffusion layer and the n-type diffusion layer is not particularly limited, and in a mixed gas atmosphere such as nitrogen, oxygen, argon, helium, xenon, neon, krypton, etc. Preferably there is.

  The temperature of the heat treatment (thermal diffusion) for forming the p-type diffusion layer and the n-type diffusion layer is preferably 800 ° C. or higher and 1100 ° C. or lower, more preferably 850 ° C. or higher and 1100 ° C. or lower, and 900 ° C. The temperature is more preferably 1100 ° C. or lower.

  Since the glass layer remains on the silicon substrate on which the p-type diffusion layer and the n-type diffusion layer are formed by the above process, it is preferable to remove the glass layer by etching. As the etching, a known method such as a method of immersing in an acid such as hydrofluoric acid or a method of immersing in an alkali such as caustic soda can be applied.

  Next, an antireflection layer or a passivation layer is formed on both sides. Here, examples of the layer that can serve as both the antireflection layer and the passivation layer include a nitride layer formed by a plasma CVD method. Examples of this layer include a thermal oxide layer, an aluminum oxide layer, a SiNx layer, an amorphous silicon layer, and the like, which can be formed by a vapor deposition method or a coating method. This layer may have a single layer structure or a multilayer structure such as a two-layer structure or a three-layer structure. For example, the thermal oxidation layer and the SiNx layer may be passivated on the silicon substrate.

Next, electrodes are formed on both sides of the silicon substrate. For the formation of the electrode, a method usually used in the technical field can be used without particular limitation.
For example, a surface electrode metal paste containing metal particles and glass particles is applied on the n-type diffusion layer forming region and the p-type diffusion layer forming region so as to have a desired shape, and this is heat-treated (fired). A surface electrode can be formed in an electrode formation region on the p-type diffusion layer and the n-type diffusion layer. As the surface electrode metal paste, for example, a silver paste or the like usually used in the technical field can be used.

<Method for producing solar cell element>
The method for manufacturing a solar cell element of the present invention includes a step of forming an electrode on a p-type diffusion layer or an n-type diffusion layer of a semiconductor substrate obtained by the above-described manufacturing method.

Below, embodiment of the manufacturing method of a solar cell element is described, referring drawings.
FIG. 1A to FIG. 1F are cross-sectional views schematically showing process drawings schematically showing an example of a method for manufacturing a back contact solar cell element according to the present embodiment. However, this process diagram does not limit the present invention.

An example in which an n-type silicon substrate is used as a semiconductor substrate will be described with reference to FIGS. First, an n-type silicon substrate 10 having a thickness of about 50 μm to 300 μm is prepared. The n-type silicon substrate 10 is formed of a single crystal or a polycrystal formed by a Czochralski method (CZ method), a floating zone method (FZ method), an edge-defined film-fed growth method (EFG method), a casting method, or the like. It is obtained by slicing a crystalline silicon ingot or the like, and has, for example, an n-type impurity such as phosphorus of about 1 × 10 ¹⁵ cm ⁻³ to 1 × 10 ¹⁹ cm ⁻³ .
Next, the n-type silicon substrate 10 is preferably washed with an alkaline aqueous solution. By washing with an alkaline aqueous solution, organic substances, particles and the like existing on the surface of the silicon substrate can be removed, and the passivation effect is further improved. As a method for cleaning with an alkaline aqueous solution, generally known RCA cleaning and the like can be exemplified. For example, the n-type silicon substrate 10 is dipped in a mixed solution of ammonia water and hydrogen peroxide water, and treated at 60 ° C. to 80 ° C., thereby removing organic substances and particles and washing them. The cleaning time is preferably 10 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes.

  Next, the n-type silicon substrate 10 shown in FIG. 1A is processed by alkali etching or the like to form a textured structure (pyramid shape, not shown) on the light receiving surface (surface), and sunlight is reflected from the light receiving surface. Suppress. Then, as shown in FIG.1 (b), the p-type diffused layer formation composition 11 is provided to a part of back surface on the opposite side to a light-receiving surface, and an n-type diffused layer formation composition is formed in a part of a light-receiving surface and a back surface. Item 12 is given. Thereafter, heat treatment is performed, and the p-type diffusion layer 13 and the n-type diffusion layer 14 are collectively formed by thermal diffusion as shown in FIG. At this time, the p-type diffusion layer forming composition 11 is a heat-treated product 11 ′ by heat treatment for thermal diffusion, and the n-type diffusion layer forming composition 12 is a heat-treated product 12 ′ by heat treatment for thermal diffusion. It has become. The p-type diffusion layer forming composition 11 is a diffusion layer forming paste containing glass particles containing boron, aluminum or gallium, and the n-type diffusion layer forming composition 12 is glass particles containing phosphorus, arsenic or antimony. A diffusion layer forming paste can be used. The thermal diffusion temperature is preferably 800 ° C to 1100 ° C. Since the p-type diffusion layer composition and the n-type diffusion layer forming composition of the present invention use glass particles having low volatility as the dopant, the dopant is difficult to volatilize even at high temperatures during thermal diffusion. Except for the portion to which the forming composition is applied, the dopant is difficult to diffuse, and therefore tends to be diffused collectively.

  As shown in FIG. 1D, the heat treatment product 11 'of the p-type diffusion layer forming composition and the heat treatment product 12' of the n-type diffusion layer forming composition are removed by immersing in an etching solution such as hydrofluoric acid.

  Next, as shown in FIG. 1E, an antireflection / passivation layer 15 is formed on the light receiving surface and the back surface. Examples of the antireflection / passivation layer 15 include a silicon nitride layer, a titanium oxide layer, a silicon oxide layer, and an aluminum oxide layer. The antireflection / passivation layer 15 may be formed on the entire back surface or a partial region, or a portion corresponding to a contact portion with the electrode may be etched. For etching, a compound such as ammonium fluoride can be used. Moreover, when the antireflection layer / passivation layer 15 is a silicon nitride layer, an ohmic contact can be obtained by using a material containing glass particles having fire-through properties as an electrode forming paste. A surface protective layer (not shown) such as silicon oxide or aluminum oxide may further exist between the antireflection layer / passivation layer 15 and the n-type silicon substrate 10, and the antireflection layer / passivation layer 15 partially. The composition may be changed.

  Thereafter, as shown in FIG. 1 (f), the electrode forming paste is applied to the back surface side, followed by heat treatment to form the p electrode 16 and the n electrode 17. By using a paste containing glass particles having fire-through properties as an electrode forming paste, even if the antireflection layer / passivation layer 15 is formed on the entire back surface, the antireflection layer / passivation layer 15 penetrates and diffuses. An ohmic contact can be obtained by forming an electrode on the layer. As described above, a solar cell element can be obtained.

  FIG. 2A to FIG. 2F are sectional views showing process drawings schematically showing an example of a method for manufacturing a double-sided light-receiving solar cell element according to the present embodiment. However, this process diagram does not limit the present invention.

An example in which an n-type silicon substrate is used as a silicon substrate will be described with reference to FIGS.
First, it is preferable to clean the n-type silicon substrate 10 with an alkaline aqueous solution. By washing with an alkaline aqueous solution, organic substances, particles and the like existing on the surface of the silicon substrate can be removed, and the passivation effect is further improved. As a method for cleaning with an alkaline aqueous solution, generally known RCA cleaning and the like can be exemplified. For example, the organic substrate and particles can be removed and washed by immersing the silicon substrate in a mixed solution of aqueous ammonia and hydrogen peroxide and treating at 60 ° C. to 80 ° C. The cleaning time is preferably 10 seconds to 10 minutes, and more preferably 30 seconds to 5 minutes.

  Next, the n-type silicon substrate 10 shown in FIG. 2A is processed by alkali etching or the like to form a texture structure (pyramid shape, not shown) on both surfaces of the substrate, thereby suppressing sunlight reflection. Thereafter, as shown in FIG. 2B, the p-type diffusion layer forming composition 11 is applied to one surface, and the n-type diffusion layer forming composition 12 is applied to the other surface. Next, heat treatment is performed, and as shown in FIG. 2C, the p-type diffusion layer 13 and the n-type diffusion layer 14 are collectively formed by thermal diffusion. At this time, the p-type diffusion layer forming composition 11 is a heat-treated product 11 ′ by heat treatment for thermal diffusion, and the n-type diffusion layer forming composition 12 is a heat-treated product 12 ′ by heat treatment for thermal diffusion. It has become. The p-type diffusion layer forming composition 11 is a diffusion layer forming paste containing glass particles containing boron, aluminum or gallium, and the n-type diffusion layer forming composition 12 is glass particles containing phosphorus, arsenic or antimony. A diffusion layer forming paste can be used. The thermal diffusion temperature is preferably 800 ° C to 1100 ° C. Since the p-type diffusion layer composition and the n-type diffusion layer forming composition of the present invention use glass particles having low volatility as the dopant, the dopant is difficult to volatilize even at high temperatures during thermal diffusion. Except for the portion to which the forming composition is applied, the dopant is difficult to diffuse, and therefore tends to be diffused collectively.

  As shown in FIG. 2D, the heat-treated product 11 'of the p-type diffusion layer forming composition and the heat-treated product 12' of the n-type diffusion layer forming composition are removed by dipping in an etching solution such as hydrofluoric acid.

  Next, as shown in FIG. 2E, an antireflection layer / passivation layer 15 is formed on the light receiving surface and the back surface. Examples of the antireflection / passivation layer 15 include a silicon nitride layer, a titanium oxide layer, a silicon oxide layer, and an aluminum oxide layer. The anti-reflection layer / passivation layer 15 may be formed on the entire surface of the light receiving surface or a part of the light receiving surface, or a portion corresponding to the contact portion with the electrode may be etched. For etching, a compound such as ammonium fluoride can be used. Moreover, when the antireflection layer / passivation layer 15 is a silicon nitride layer, an ohmic contact can be obtained by using a material containing glass particles having fire-through properties as an electrode forming paste. A surface protective layer (not shown) such as silicon oxide or aluminum oxide may further exist between the antireflection layer / passivation layer 15 and the n-type silicon substrate 10, and the antireflection layer / passivation layer 15 partially. The composition may be changed.

  Thereafter, as shown in FIG. 2 (f), an electrode forming paste is applied to each of the light receiving surface and the back surface, and then heat treatment is performed to form the p electrode 16 and the n electrode 17. By using a paste containing glass particles having fire-through properties as an electrode forming paste, even if the antireflection layer / passivation layer 15 is formed on the entire back surface, the antireflection layer / passivation layer 15 penetrates and diffuses. An ohmic contact can be obtained by forming an electrode on the layer. As described above, a solar cell element can be obtained.

<Solar cell element>
The solar cell element of the present invention is obtained by the above-described manufacturing method. Thereby, the solar cell element of this invention suppresses that a diffused layer is formed in the unnecessary area | region of a semiconductor substrate, and the improvement of battery performance is aimed at.
In the solar cell element, a wiring material such as a tab wire may be disposed on the electrode, and a plurality of solar cell elements may be connected via the wiring material to constitute a solar cell module. Furthermore, the solar cell module may be configured by being sealed with a sealing material.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise noted, all reagents used reagents. Unless otherwise specified, “part” means “part by mass” and “%” means “mass%”.

[Example 1]
Glass particles having a substantially spherical shape, D50% of 0.35 μm, and softening point of about 800 ° C. (mainly composed of B ₂ O ₃ , SiO ₂ and CaO, the respective contents are 30% by mass and 50% by mass) And 20% by mass) 10 g of ethyl cellulose, 6 g of ethyl cellulose, and 84 g of terpineol were mixed to form a paste to prepare a p-type diffusion layer forming composition.

Glass particles having a substantially spherical particle shape, an average particle diameter of 0.31 μm, and a softening point of about 800 ° C. (mainly composed of P ₂ O ₅ , SiO ₂ and CaO, the respective contents are 30% by mass, 60% by mass) % And 10% by mass) 10 g, 6 g of ethyl cellulose, and 84 g of terpineol were mixed into a paste to prepare an n-type diffusion layer forming composition.

  The glass particle shape was determined by observing using Hitachi High-Technologies Corporation, TM-1000 scanning electron microscope. The average particle size of the glass was calculated using a Beckman Coulter Co., Ltd., LS 13 320 type laser scattering diffraction particle size distribution analyzer (measurement wavelength: 632 nm). The softening point of the glass was obtained from a differential thermal analysis (DTA) curve using Shimadzu Corporation, a DTG-60H type differential thermal / thermogravimetric simultaneous measurement apparatus. In the differential thermal analysis measurement, α-alumina was used as a reference, the heating rate was 10 K / min, and air was flowed at 5 mL / min. The second endothermic peak of the differential curve of the obtained DTA curve was calculated as the softening point.

  Next, the p-type diffusion layer forming composition was applied to one surface of the n-type silicon substrate in a solid form by screen printing and dried at 150 ° C. for 1 minute. Subsequently, the n-type diffusion layer forming composition is applied to the other surface of the n-type silicon substrate (the surface on which the p-type diffusion layer forming composition is not applied) by screen printing, and then at 150 ° C. for 1 minute. Dried.

Next, in a diffusion furnace (Koyo Thermo System Co., Ltd., 206A-M100) in which O ₂ : ₂ L / min and N ₂ : 8 L / min are flowed, p-type and n-type are set at 700 ° C. The substrate provided with the diffusion layer composition was put in, heated to 950 ° C. at 15 ° C./min, and heat-treated at 950 ° C. for 30 minutes. Thereafter, the temperature was lowered to 700 ° C. at 10 ° C./min, boron and phosphorus were diffused in the n-type silicon substrate, and a p-type diffusion layer and an n-type diffusion layer were formed in a lump.
Subsequently, the n-type silicon substrate was immersed in hydrofluoric acid for 5 minutes and washed with running water to remove the glass layer remaining on the surface of the silicon substrate.
The average value of the sheet resistance of the portion (electrode formation region) coated with the p-type diffusion layer forming composition is 45Ω / □, and the average of the sheet resistance of the portion (electrode formation region) coated with the n-type diffusion layer forming composition. The value was 12Ω / □.

  Next, the edge (side surface) of the silicon substrate was immersed in a 10% NaOH aqueous solution heated to 80 ° C. for 1 minute to perform edge isolation.

  Next, an antireflection layer was formed by vapor-depositing silicon nitride on the surface on which the n-type diffusion layer was formed. In addition, on the surface on which the p-type diffusion layer was formed, aluminum oxide was deposited by an ALD (Atomic Layer Deposition) method to form a passivation layer.

Next, a silver electrode (DuPont, PV159A) was formed on each side of the substrate by screen printing using a printing mask. Subsequently, after drying at 150 degreeC, it baked at 700 degreeC using the tunnel-type baking furnace (Corporation Noritake Co., Ltd.), and produced the solar cell element. The generated solar cell element was evaluated for power generation characteristics using a solar simulator (Wacom Electric Power Co., Ltd., XS-155S-10).
The power generation performance of the produced solar cell element is expressed as Jsc (short circuit current density), Voc (open voltage), F.R. F. (Curve factor) and η (conversion efficiency). Jsc, Voc, F.M. F. And η were obtained by measuring according to JIS C8913 (2005) and JIS C8914 (2005), respectively, 29.85 mA / cm ² , 589 mV, 0.76, and 13. It was 5%.

[Comparative Example 1]
Boron oxide (10 g), ethyl cellulose (6 g), and terpineol (84 g) were mixed to form a paste to prepare p-type diffusion layer forming composition C.

  N-type diffusion layer forming composition C was prepared by mixing 10 g of ammonium dihydrogen phosphate, 6 g of ethyl cellulose, and 84 g of terpineol to form a paste.

Except for using the p-type diffusion layer forming composition C and the n-type diffusion layer forming composition C in place of the p-type diffusion layer forming composition and the n-type diffusion layer forming composition, the same as in Example 1, A solar cell element was produced and evaluated.
The power generation performance of the produced solar cell element is expressed as Jsc (short circuit current density), Voc (open voltage), F.R. F. (Curve factor) and η (conversion efficiency). Jsc, Voc, F.M. F. And η were 28.78 mA / cm ² , 567 mV, 0.76, and 12.4%, respectively.

  As described above, the solar cell element of Example 1 manufactured using the p-type diffusion layer forming composition and the n-type diffusion layer forming composition is composed of the p-type diffusion layer forming composition C and the n-type diffusion layer forming composition C. Compared with the solar cell element of Comparative Example 1 using the short circuit current density and the open circuit voltage are excellent. In Comparative Example 1, since the p-type diffusion layer and the n-type diffusion layer are not appropriately formed at desired positions, there is a problem in forming a pn junction. For example, the charge depletion layer is thick and the electric field there is Since it is weak, it can be understood that separation of electrons and holes hardly occurs and there are problems such as easy leakage. On the other hand, the effect of Example 1 which formed the p-type diffusion layer and the n-type diffusion layer using the glass particle containing a donor element or an acceptor element was able to be confirmed easily.

  The disclosure of Japanese Patent Application No. 2013-264589 filed on December 20, 2013 is incorporated herein by reference in its entirety. All documents, patent applications and technical standards mentioned in this specification are to the same extent as if each individual document, patent application and technical standard were specifically and individually stated to be incorporated by reference. Incorporated by reference in the book.

Claims (11)

An n-type diffusion layer forming composition containing glass particles containing a donor element and a dispersion medium, and a p-type diffusion layer forming composition containing glass particles containing an acceptor element and a dispersion medium on at least a part of the semiconductor substrate. Applying to different areas,
Forming an n-type diffusion layer by performing heat treatment and forming a p-type diffusion layer;
A method for manufacturing a semiconductor substrate having a diffusion layer comprising:   The method for manufacturing a semiconductor substrate having a diffusion layer according to claim 1, wherein the n-type diffusion layer and the p-type diffusion layer are collectively formed in the step of performing the heat treatment.   The manufacturing method of the semiconductor substrate which has a diffused layer of Claim 1 or Claim 2 in which the said donor element contains at least 1 sort (s) selected from the group which consists of P (phosphorus) and Sb (antimony). The glass particles containing the donor element include at least one donor element-containing material selected from the group consisting of P ₂ O ₃ , P ₂ O ₅ and Sb ₂ O ₃ ; and SiO ₂ , K ₂ O, Na ₂ O At least one glass component material selected from the group consisting of Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ and MoO _3. The manufacturing method of the semiconductor substrate which has a diffusion layer of any one of Claims 1-3 which contains.   The said acceptor element contains at least 1 sort (s) of element selected from the group which consists of B (boron), Al (aluminum), and Ga (gallium), The any one of Claims 1-4. A method for manufacturing a semiconductor substrate having a diffusion layer. The glass particles containing the acceptor element are at least one acceptor element-containing material selected from the group consisting of B ₂ O ₃ , Al ₂ O ₃ and Ga ₂ O ₃ , and SiO ₂ , K ₂ O, Na ₂ O. , Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, Tl ₂ O, V ₂ O ₅ , SnO, ZrO ₂ , WO ₃ , MoO ₃ and MnO. The manufacturing method of the semiconductor substrate which has a diffusion layer of any one of Claims 1-5 containing 1 type of glass component substance.   The method for manufacturing a semiconductor substrate having a diffusion layer according to any one of claims 1 to 6, further comprising a step of forming a passivation layer on at least one of the n-type diffusion layer and the p-type diffusion layer. .   The manufacture of a semiconductor substrate having a diffusion layer according to any one of claims 1 to 7, wherein the passivation layer contains at least one selected from the group consisting of silicon oxide, silicon nitride, and aluminum oxide. Method.   A semiconductor substrate having an n-type diffusion layer and a p-type diffusion layer, which is obtained by the manufacturing method according to claim 1.   The manufacturing method of a solar cell element which has the process of forming an electrode on the n type diffused layer of a semiconductor substrate obtained by the manufacturing method of any one of Claims 1-8, and a p type diffused layer .   The solar cell element obtained by the manufacturing method of Claim 10.