JP5935255B2 - Impurity diffusion layer forming composition for inkjet, method for producing impurity diffusion layer, method for producing solar cell element, and method for producing solar cell - Google Patents

Description

The present invention is an inkjet impurity diffusion layer forming composition, manufacturing how the impurity diffusion layer, a method of manufacturing a manufacturing method and a solar cell of the solar cell element.

  Conventionally, in the manufacture of solar cells, when a p-type impurity diffusion layer is formed only in a specific region on a semiconductor substrate, for example, a diffusing agent containing a p-type impurity diffusion component is patterned on the surface of the semiconductor substrate, A p-type impurity diffusion layer is formed by diffusing a p-type impurity diffusion component from the patterned diffusing agent. Specifically, a thermal oxide film is first formed on the surface of the semiconductor substrate, then a resist having a predetermined pattern is laminated on the thermal oxide film by photolithography, and a diffusing agent is applied using the resist as a mask. The impurity diffusion component in the diffusing agent is diffused to form a p-type impurity diffusion layer in the semiconductor substrate.

  Thus, conventionally, many steps have to be performed in order to form an impurity diffusion layer only in a specific region on a semiconductor substrate. In connection with this, a method of patterning a diffusing agent on the surface of a semiconductor substrate using an inkjet method has been proposed (see, for example, Patent Documents 1 to 3). In the inkjet method, patterning is performed by ejecting a diffusing agent from an inkjet nozzle to a p-type impurity diffusion layer forming region without using a mask, so that a complicated process is not required compared to a conventional photolithography method and the like. It is said that a pattern can be formed.

JP 2003-168810 A JP 2003-332606 A JP 2006-156646 A

  However, in the patterning method using the above-described inkjet method, it may be difficult to selectively form an impurity diffusion layer depending on the type of impurity diffusion component contained in the impurity diffusion layer forming composition used. . That is, when the impurity diffusion component is highly volatile at a high temperature for forming the impurity diffusion layer, the diffusion layer is formed by the volatilized impurity diffusion component in addition to the region selectively applied with the impurity diffusion layer forming composition by the inkjet method. There was a problem of forming (out diffusion).

  The present invention has been made in view of the above conventional problems, and an impurity diffusion layer for pattern formation by an ink jet method capable of suppressing the formation of an impurity diffusion layer in a region other than a desired region on a semiconductor substrate. It is providing the formation composition and the manufacturing method of the impurity diffusion layer using the said impurity diffusion layer formation composition.

Specific means for solving the above problems are as follows.
<1> Glass particles containing a donor element and inorganic particles containing at least one donor element selected from the group consisting of particles containing a reaction product of a silicon alkoxide and a phosphorus compound, or glass particles containing an acceptor element, boron nitride An impurity diffusion layer forming composition for inkjet, comprising inorganic particles containing at least one acceptor element selected from the group consisting of particles and particles containing a reaction product of silicon alkoxide and a boron compound, and a dispersion medium.

<2> The impurity diffusion layer forming composition according to <1>, wherein the glass particles containing the donor element contain at least one kind of donor element selected from P (phosphorus) and Sb (antimony).

<3> The glass particles containing the donor element include at least one donor element-containing material selected from P ₂ O ₃ , P ₂ O ₅ and Sb ₂ O ₃ , SiO ₂ , K ₂ O, and Na ₂ O. And at least one glass component material selected from Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ , and MoO _3. The impurity diffusion layer forming composition as described in <1> or <2>.

<4> The impurity diffusion layer type according to <1>, wherein the glass particle containing the acceptor element contains at least one acceptor element selected from B (boron), Al (aluminum), and Ga (gallium). Narugumi Narubutsu.

<5> The glass particles containing the acceptor element include at least one acceptor element-containing substance selected from B ₂ O ₃ , Al ₂ O _3, and Ga ₂ O ₃ , and SiO ₂ , K ₂ O, and Na ₂ O. And at least one glass component material selected from Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ , and MoO _3. <1> or impurity diffusion layers form Narugumi composition as described in <4>.

<6> The impurity diffusion layer forming composition according to any one of <1> to <5>, wherein the dispersion medium includes at least one selected from water and an organic solvent.

<7> The impurity diffusion layer forming composition according to any one of <1> to <6>, wherein the dispersion medium includes a water-soluble polymer compound.

<8> The impurity diffusion layer forming composition according to any one of <1> to <7>, wherein the content of the inorganic particles containing the donor element or the inorganic particles containing the acceptor element is 1 to 30% by mass. .

<9> The impurity diffusion layer forming composition according to any one of <1> to <8>, further including a thixotropic agent.

<10> The impurity diffusion layer forming composition according to any one of <1> to <9>, further including a surfactant.

<11> A step of forming the composition layer in a pattern by discharging the impurity diffusion layer forming composition according to any one of <1> to <10> on a semiconductor substrate by an inkjet method; And a step of heat-treating the semiconductor substrate on which the composition layer is formed to diffuse the donor element or the acceptor element into the semiconductor substrate.

<12> The method for producing an impurity diffusion layer according to <11>, wherein the composition layer is a linear pattern, and the line width is 10 μm to 100 μm.

<13> to <11> or <12> The impurity diffusion layer of a semiconductor substrate in which an impurity diffusion layer is formed by the production method of the impurity diffusion layer described in the preparation of a solar cell element including a step of forming an electrode Way .

<14> the on the electrode of the solar cell device manufactured by the manufacturing method of the solar battery cell according to <13>, method of manufacturing a solar cell comprising a step of placing a tab line.

  According to the present invention, an impurity diffusion layer forming composition for pattern formation by an inkjet method capable of suppressing the formation of an impurity diffusion layer in a region other than a desired region on a semiconductor substrate, and the impurity diffusion layer forming composition are used. It is possible to provide a method for manufacturing an impurity diffusion layer and a method for manufacturing a solar cell element.

It is sectional drawing which shows notionally an example of the manufacturing process of the solar cell element of this invention. (A) is the top view which looked at the solar cell element from the surface, (B) is the perspective view which expands and shows a part of (A). It is sectional drawing which shows notionally an example of the manufacturing process of the solar cell element concerning this invention.

First, an impurity diffusion layer forming composition of the present invention will be described, and then an impurity diffusion layer using the diffusion layer forming composition and a method for manufacturing a solar cell element will be described.
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, when referring to the amount of each component in the composition in the present specification, when there are a plurality of substances corresponding to each component in the composition, the plurality of the components present in the composition unless otherwise specified. It means the total amount of substance.

<Impurity diffusion layer forming composition>
The impurity diffusion layer forming composition of the present invention is an inorganic particle or acceptor containing at least one donor element selected from the group consisting of glass particles containing a donor element and particles containing a reaction product of silicon alkoxide and a phosphorus compound. Comprising inorganic particles containing at least one acceptor element selected from the group consisting of glass particles containing elements, boron nitride particles and particles containing a reaction product of silicon alkoxide and a boron compound, and a dispersion medium. , And used for forming a patterned impurity diffusion layer forming composition layer (hereinafter also simply referred to as “composition layer”) by an inkjet method. The impurity diffusion layer forming composition may contain other components as required.
When the composition for forming an impurity diffusion layer has the above-described configuration, it is possible to suppress the formation of an impurity diffusion layer (out diffusion) in a region other than a desired region on the semiconductor substrate. It is suitably used for applications (hereinafter also simply referred to as “inkjet”).

Here, the impurity diffusion layer forming composition contains inorganic particles containing a donor element or an acceptor element and a dispersion medium, and is applied to a semiconductor substrate and then thermally diffuses the donor element or the acceptor element to thereby diffuse the impurity diffusion layer. Refers to a material capable of forming
In this specification, the “n-type diffusion layer” and the “p-type diffusion layer” may be collectively referred to as “impurity diffusion layer”.

The impurity diffusion layer forming composition comprises inorganic particles or acceptor elements containing at least one donor element selected from the group consisting of glass particles containing a donor element and particles containing a reaction product of a silicon alkoxide and a phosphorus compound. By including specific inorganic particles such as inorganic particles containing at least one acceptor element selected from the group consisting of glass particles, boron nitride particles and particles containing a reaction product of silicon alkoxide and a boron compound, a donor element or Outdiffusion of the compound containing the acceptor element is suppressed, and an impurity diffusion layer can be formed only in a desired region.
The patterned composition layer formed on the semiconductor substrate using the impurity diffusion layer forming composition corresponds to a region on the semiconductor substrate where an impurity diffusion layer formed by a thermal diffusion process described later is formed. In the present invention, no impurity diffusion layer is formed in a region other than the pattern.
Moreover, the area | region which forms an impurity diffusion layer with high precision can be controlled by providing the said impurity diffusion layer forming composition on a semiconductor substrate with an inkjet system.

The impurity diffusion layer forming composition contains specific inorganic particles containing a donor element or specific inorganic particles containing an acceptor element. When the impurity diffusion layer forming composition contains specific inorganic particles containing a donor element, an n-type diffusion layer can be formed. When the impurity diffusion layer forming composition contains specific inorganic particles containing an acceptor element, a p-type diffusion layer can be formed.
The specific inorganic particle containing the donor element is at least one selected from the group consisting of glass particles containing a donor element and phosphorus-containing silicon oxide particles containing a reaction product of a silicon alkoxide and a phosphorus compound.
The specific inorganic particles containing the acceptor element are at least one selected from the group consisting of glass particles containing an acceptor element, boron nitride particles, and boron-containing silicon oxide particles containing a reaction product of silicon alkoxide and a boron compound. It is a seed.

(Glass particles containing donor elements)
By using glass particles containing a donor element as inorganic particles containing a donor element, an n-type diffusion layer can be formed only in a desired region. That is, since the donor component in the glass powder is not easily volatilized even during firing, the generation of the volatilizing gas suppresses the formation of the n-type diffusion layer not only on the surface but also on the back surface and side surfaces. The reason for this is considered that the donor component is bonded to an element in the glass powder or is taken into the glass, so that it is difficult to volatilize.
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), As (arsenic), and the like. From the viewpoints of safety, ease of vitrification, etc., P or Sb is preferred.

Examples of the donor element-containing material used for introducing the donor element into the glass particles include P ₂ O ₃ , P ₂ O ₅ , Sb ₂ O ₃ , Bi ₂ O _3, and As ₂ O ₃ , and P ₂ O ₃ It is preferable to use at least one selected from P ₂ O ₅ and Sb ₂ O ₃ .

Moreover, the glass particle containing a donor element can control a melting temperature, a softening temperature, a glass transition temperature, chemical durability, etc. by adjusting a component ratio as needed. Furthermore, it is preferable to contain the glass component substance described below. Confirmation of the glass component can be performed by powder X-ray diffraction. Specifically, it can be confirmed from the powder X-ray diffraction pattern that it is amorphous.
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, SnO, ZrO ₂ , MoO ₃ , La ₂ O ₃ , Examples include Nb ₂ O ₅ , Ta ₂ O ₅ , Y ₂ O ₃ , TiO ₂ , ZrO ₂ , GeO ₂ , TeO _2, and Lu ₂ O _3, and include SiO ₂ , K ₂ O, Na ₂ O, Li ₂ O. It is preferable to use at least one selected from BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, SnO, ZrO ₂ , and MoO ₃ .

Specific examples of the glass particles containing a donor element include a system containing both the donor element-containing substance and the glass component substance, and a P ₂ O ₅ —SiO ₂ system (in order of donor element-containing substance-glass component substance). in described, the same applies _{hereinafter), P 2 O 5 -K 2} O _based, P ₂ O 5 -Na _{2 O-based,} P ₂ O 5 -Li ₂ O _system, P ₂ O 5 _-BaO-based, P 2 _{O 5} - _SrO-based, P ₂ O 5 _-CaO-based, P ₂ O 5 _-MgO-based, P ₂ O 5 -BeO _based, P ₂ O 5 _-ZnO-based, P ₂ O 5 -CdO _based, P ₂ O 5 -PbO system , including _P 2 _O 5 _-V 2 _{O 5 system,} P ₂ O 5 _-SnO-based, P ₂ O 5 -GeO _{2 system,} a _P 2 _{O 5} as a donor element-containing material of P ₂ O 5 -TeO ₂ system, etc. Instead of P ₂ O ₅ in a system containing P ₂ O ₅ , a donor element-containing material is used. And glass particles of a system containing Sb ₂ O ₃ .
Note that glass particles containing two or more kinds of donor element-containing substances may be used, such as P ₂ O ₅ —Sb ₂ O ₃ system and P ₂ O ₅ —As ₂ O ₃ system.
Although the composite glass containing two components was illustrated above, glass particles containing three or more components such as P ₂ O ₅ —SiO ₂ —V ₂ O ₅ and P ₂ O ₅ —SiO ₂ —CaO may be used.

The glass particles include at least one phosphorus element-containing material selected from P ₂ O ₃ and P ₂ O ₅ , SiO ₂ , K ₂ O, Na ₂ O, Li ₂ O, BaO, SrO, CaO, and MgO. And at least one glass component selected from BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ , MoO ₃ , GeO ₂ , Y ₂ O ₃ , CsO ₂ and TiO ₂ It is preferable to include a phosphorus element-containing material that is P ₂ O ₅ and at least one glass component material selected from SiO ₂ , ZnO, CaO, Na ₂ O, Li ₂ O, and BaO. More preferred. Thereby, the sheet resistance of the n-type diffusion layer to be formed can be further reduced.

  The content ratio of the donor element-containing substance in the glass particles may be appropriately set in consideration of the doping concentration of the donor element into the semiconductor substrate, the melting temperature, the softening temperature, the glass transition temperature, and the chemical durability of the glass particles. Desirably, generally, it is preferably 1% by mass or more and 75% by mass or less.

When the content ratio of the donor element-containing substance in the glass particles is 1% by mass or more, the doping concentration of the donor element into the semiconductor substrate does not become too low, and the n-type diffusion layer is sufficiently formed. Further, when the content ratio of the donor element-containing substance such as P ₂ O ₅ is 75% by mass or less, the donor element-containing substance absorbs moisture in the glass particles. For example, when the donor element-containing substance is P ₂ O ₅ Can suppress the formation of phosphoric acid (H ₃ PO ₄ ). As a result, moisture-absorbing substances such as H ₃ PO ₄ are suppressed from being volatilized during the thermal diffusion treatment, and the diffusion of the donor element such as P (phosphorus) extends to the side surface and the back surface as well as the surface. It is possible to prevent the n-type diffusion layer from being formed on the side surface and the back surface other than the part.

  Further, a sheet having a surface having an n-type diffusion layer formed even when a certain amount or more of a donor element is added to the composition for forming an n-type diffusion layer while taking into account the amount of the donor element in which the n-type diffusion layer is sufficiently formed Considering that the resistance does not decrease beyond a certain value and that it is necessary to suppress the influence of volatilization of the donor element-containing substance, the content of the donor element-containing substance in the glass particles is 2% by mass or more and 75% by mass. % Or less, and more preferably 10% by mass or more and 70% by mass or less.

In particular, in consideration of suppressing the influence of volatilization of a hygroscopic substance such as H ₃ PO ₄ without changing the sheet resistance of the surface after the heat treatment on the side where the n-type diffusion layer forming composition is applied, The content ratio of the donor element-containing material is more preferably 30% by mass or more and 70% by mass or less.

  Further, the content ratio of the glass component substance in the glass particles is preferably set as appropriate in consideration of the melting temperature, the softening temperature, the glass transition temperature, and the chemical durability, and generally 0.1% by mass or more and 95% by mass. % Or less, more preferably 0.5% by mass or more and 90% by mass or less.

Specifically, in the case of P ₂ O ₅ —SiO ₂ glass, the content ratio of SiO ₂ is preferably 1% by mass to 90% by mass, and preferably 3% by mass to 80% by mass. It is more preferable.

(Glass particles containing acceptor elements)
By using glass particles containing an acceptor element as inorganic particles containing an acceptor element, a p-type diffusion layer can be formed only in a desired region. That is, since the acceptor component in the glass powder is difficult to volatilize even during firing, the generation of the volatilizing gas suppresses the formation of the p-type diffusion layer not only on the surface but also on the back surface and side surfaces. The reason for this is considered that the acceptor component is bonded to an element in the glass powder or is taken into the glass, so that it is difficult to volatilize.
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).

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 ₂ O. It is preferable to use at least one selected from ₃ .

Moreover, the glass particle containing an acceptor element can control a melting temperature, a softening temperature, a glass transition temperature, chemical durability, etc. by adjusting a component ratio as needed. Furthermore, it is preferable to contain the components described below. Confirmation of the glass component can be performed by powder X-ray diffraction. Specifically, it can be confirmed from the powder X-ray diffraction pattern that it is amorphous.
As the glass ingredient _{material, SiO 2, Bi 2 O 3} , K 2 O, Na 2 O, Li 2 O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, Tl 2 O, SnO, ZrO 2 , MoO ₃ , La ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Y ₂ O ₃ , TiO ₂ , GeO ₂ , TeO _2, and Lu ₂ O _{3, and the} like, SiO ₂ , Bi ₂ O ₃ , K _{Use of} at least one selected from ₂ O, Na ₂ O, Li ₂ O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, Tl ₂ O, SnO, ZrO ₂ , and MoO ₃ Preferably, at least one selected from SiO ₂ , Bi ₂ O ₃ , ZnO, CaO, Na ₂ O, Li ₂ O and BaO is more preferable.

Specific examples of the glass particles containing an acceptor element include a system containing both the acceptor element-containing substance and the glass component substance, and a B ₂ O ₃ —SiO ₂ system (in order of acceptor element-containing substance—glass component substance). And the same applies hereinafter), B ₂ O ₃ —ZnO system, B ₂ O ₃ —PbO system, B ₂ O ₃ single system, etc., a system containing B ₂ O ₃ as an acceptor element-containing substance, Al ₂ O ₃ —SiO ₂ Glasses such as a system containing Al ₂ O ₃ as an acceptor element-containing material such as a ₂ system and a system containing Ga ₂ O ₃ as an acceptor element containing material such as a Ga ₂ O ₃ —SiO ₂ system can be given.
_{Further, Al 2 O 3 -B 2 O} 3 _system, such as the Ga _{2 O 3 -B 2} O 3 system or the like, may be glass particles containing two or more acceptor element-containing material.
In the above, a single component glass or a composite glass containing two components has been exemplified, but three or more types of composite glasses such as B ₂ O ₃ —SiO ₂ —Na ₂ O may be used as necessary.

  The content ratio of the glass component substance in the glass particles is preferably set in consideration of the melting temperature, the softening temperature, the glass transition temperature, 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.

(Properties of glass particles)
When the impurity diffusion layer forming composition includes glass particles containing a donor element or glass particles containing an acceptor element (hereinafter also referred to simply as “glass particles”), the glass particles exhibit the following properties: Is preferred.
The softening point of the glass particles is preferably 200 ° C. to 1200 ° C., and more preferably 300 ° C. to 900 ° C., from the viewpoints of diffusibility during the diffusion treatment and dripping. The temperature at which the donor element or acceptor element is diffused into the semiconductor substrate is usually 600 ° C. to 1200 ° C., and if the softening point is 1200 ° C. or less, the glass particles melt at the time of thermal diffusion and contact between the molten glass and the semiconductor substrate is achieved. Is sufficiently performed and diffusion tends to be performed uniformly.

  There is no problem even if a crystal phase partially precipitates in the glass particles, and crystallized glass can also be used.

Examples of the shape of the glass particles include a substantially spherical shape, a flat shape, a block shape, a plate shape, a scale shape, and the like. From the viewpoint of application property to a substrate and a uniform diffusibility when it is an n-type diffusion layer forming composition, It is desirable to have a substantially spherical shape, a flat shape, or a plate shape. The particle size of the glass particles is preferably 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 preferably 50 μm or less, and even more preferably 10 μm or less, from the viewpoint of ejection stability in the ink jet system. The lower limit is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.5 μm or more from the viewpoint of dispersion stability.
Here, the particle diameter of the glass particles represents a volume average particle diameter, and can be measured by a laser scattering diffraction method particle size distribution measuring apparatus or the like.

Glass particles containing a donor element or an acceptor element are produced by the following procedure.
First, raw materials, for example, the donor element-containing material or acceptor-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, which are appropriately selected in consideration of the melting temperature, atmosphere, reactivity with the molten material, 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.
Subsequently, the obtained melt is poured onto a zirconia substrate, a carbon substrate or the like to vitrify the melt.
Finally, the glass is crushed into powder. A known method 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 in the impurity diffusion layer forming composition is determined in consideration of ejection stability by an ink jet method, diffusibility of a donor element and an acceptor element, and the like. When the said impurity diffusion layer forming composition contains a glass particle, it is preferable that the content rate of the glass particle in an impurity diffusion layer forming composition is 1 mass%-30 mass%, and it is 5 mass%-25 mass%. It is more preferable.
When the content is 1% by mass or more, sufficient donor element or acceptor element diffusion capability is obtained, and the resistance of the semiconductor substrate on which the impurity diffusion layer is formed tends to be easily reduced. Further, when the content is 30% by mass or less, the ejection property of the impurity diffusion layer forming composition by the ink jet method tends to be further improved.

(Boron nitride particles)
The boron nitride particles are not particularly limited as long as they contain boron nitride. The boron nitride particles may further contain other boron compounds other than boron nitride and oxides derived from boron nitride as necessary.
When the impurity diffusion layer forming composition includes boron nitride, the hygroscopicity and the reactivity with the dispersion medium can be suppressed, and the storage stability is improved. In addition, when a silicon substrate is used as the semiconductor substrate, generation of a reaction product with silicon derived from a boron compound can be suppressed during the thermal diffusion treatment, and a p-type diffusion layer having excellent characteristics can be formed. This may be because, for example, boron nitride has higher chemical stability than other boron compounds.
Furthermore, since the boron nitride particles are dispersed in a dispersion medium described later, a p-type diffusion layer in which the diffusion state of boron atoms is more uniform can be formed.

Examples of the particle shape of the boron nitride particles include a substantially spherical shape, a flat shape, a block shape, a plate shape, a scale shape, and the like, and a substantially spherical shape from the viewpoint of application property to a substrate and uniform diffusibility when used as a diffusing agent. It is preferably flat or plate-like, and more preferably flat or plate-like. By using flat or plate-like boron nitride particles having a high aspect ratio, boron nitride particles are easily oriented when an impurity diffusion layer forming composition containing boron nitride particles is applied to a semiconductor substrate. The resistance of the mold diffusion layer can be reduced.
Although the detailed reason is unknown, the orientation of the boron nitride particles during thermal diffusion makes it easier to cover the semiconductor substrate with the boron nitride particles, and the boron compound particles diffuse from the boron nitride particles to the outside air. It is considered that the diffusion of boron atoms is promoted because the boron compound gas and the semiconductor substrate are more easily contacted with each other.

  The volume average particle diameter of the boron nitride particles is preferably 10 nm to 15 μm, and more preferably 50 nm to 10 μm. The volume average particle diameter in the present invention refers to a median diameter and can be measured by a laser scattering diffraction method particle size distribution measuring apparatus or the like.

The boron nitride particles are preferably those subjected to mechanical surface modification treatment. Thereby, the diffusibility of a boron atom improves more. The mechanical surface modification treatment referred to here is a method of modifying the surface by changing the physicochemical state of the particle surface by a method of pulverizing boron nitride particles or a method of applying a shearing force to the boron nitride particles. Point to. Among these, it is preferable to perform pulverization.
Examples of the pulverization process include a dry pulverization process and a wet pulverization process. Examples of the dry pulverization process include a pulverization process using a jet mill, a vibration mill, a ball mill, and the like. Examples of the wet pulverization treatment include a method of pulverization in a dispersion medium using a bead mill, a ball mill or the like.
When impurities due to the pulverization apparatus are mixed into the boron nitride particles during the pulverization process, the dopant characteristics may be deteriorated. Therefore, materials for the pulverization container, beads, balls, etc. that have little influence on the dopant characteristics may be selected. preferable. Specifically, nylon, alumina, partially stabilized zirconia, or the like can be used.

  The pulverization treatment of the boron nitride particles is preferably a wet pulverization treatment from the viewpoint of reducing the resistance of the p-type diffusion layer. The dispersion medium used for the wet pulverization treatment is not particularly limited, and may be water, a solvent, or a mixed solvent thereof.

  Specific examples of the solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-iso-propyl ketone, methyl-n-butyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, and methyl-n-hexyl ketone. , Ketone solvents such as diethyl ketone, dipropyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone; diethyl ether, methyl ethyl ether, Methyl-n-propyl ether, di-iso-propyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane, dimethyldioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether Ter, ethylene glycol di-n-propyl ether, ethylene glycol dibutyl 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, G Ethylene glycol methyl-n-hexyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetradiethylene glycol methyl ethyl ether, tetraethylene glycol methyl n-butyl ether, diethylene 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, zip Lopylene 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, tetradipropylene glycol methyl ethyl Ether, tetrapropylene glycol methyl-n-butyl ether Ether solvents such as dipropylene glycol di-n-butyl ether, tetrapropylene glycol methyl-n-hexyl ether, tetrapropylene glycol di-n-butyl ether; methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, acetic acid n-butyl, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 2- (2- Butoxyethoxy) ethyl, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, methyl acetoacetate, ethyl acetoacetate, diethylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol acetate Methyl ether, dipropylene glycol ethyl ether, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate, diethyl oxalate, di-n-butyl oxalate, lactic acid Methyl, 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 Ester solvents such as glycol ethyl ether acetate, propylene glycol propyl ether acetate, γ-butyrolactone, γ-valerolactone; N-methylpyrrolidinone, N-ethylpyrrolidinone, N-propylpyrrolidinone, N-butylpyrrolidinone, N-hexylpyrrolidinone, N-cyclohexylpyrrolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, etc. Aprotic polar solvent: methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n-pentanol, i-pentanol, 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, ethylene glycol, Alcohol solvents such as 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monophenyl ether, Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Mono-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether And terpene solvents such as α-terpinene, α-terpineol, myrcene, alloocimene, limonene, dipentene, α-pinene, β-pinene, terpineol, carvone, ocimene, and ferrandolene. These are used singly or in combination of two or more.

Of these, water is preferably used as the dispersion medium. This facilitates the management of purity and tends to facilitate the pulverization of boron nitride particles.
When the dispersion medium at the time of the pulverization process is different from the dispersion medium of the impurity diffusion layer forming composition, the dispersion medium can be dried after the pulverization process and again dispersed in another dispersion medium. By performing the mechanical pulverization treatment, the diffusion ability tends to be improved even for boron nitride particles having high crystallinity.

  The treatment conditions in the pulverization process are not particularly limited, and can be appropriately selected according to the pulverization apparatus used, the dispersion medium, and the like.

Examples of the surface modifying device other than the pulverizing device include known surface modifying devices (Mechanofusion manufactured by Hosokawa Micron, Nobilta, Hybridizer manufactured by Nara Machinery, etc.).
The treatment conditions in the mechanical surface modification treatment using a surface modification device other than the pulverizer are not particularly limited, and can be appropriately selected according to the surface modification device to be used.

  The crystal form of the boron nitride particles may be any of hexagonal, cubic, and rhombohedral, but the particle diameter can be easily controlled and the orientation can be improved. To hexagonal crystals are preferred.

  The method for preparing the boron nitride particles is not particularly limited, and can be prepared by a usual method. For example, a method in which boron powder is heated to 1500 ° C. or higher in a nitrogen stream, a method in which molten boric acid and nitrogen or ammonia are reacted in the presence of calcium phosphate, boric acid or an alkali boride, urea, guanidine, melamine, etc. Examples include a method of reacting an organic nitrogen compound in a high-temperature nitrogen-ammonia atmosphere, a method of reacting molten sodium borate and ammonium chloride in an ammonia atmosphere, and a method of reacting boron trichloride and ammonia at a high temperature. However, there is no problem with the manufacturing method other than the above. Among the above production methods, since a high-purity boron nitride can be obtained, it is preferable to use a method of reacting boron trichloride and ammonia at a high temperature.

The content ratio of boron nitride particles in the impurity diffusion layer forming composition is determined in consideration of ejection stability by an ink jet method, boron diffusibility, and the like. When the impurity diffusion layer forming composition contains boron nitride particles, the content ratio of the boron nitride particles in the impurity diffusion layer forming composition is preferably 1% by mass to 30% by mass, and 5% by mass to 25% by mass. % Is more preferable.
When the content is 1% by mass or more, sufficient boron diffusion ability is obtained, and the resistance of the semiconductor substrate on which the p-type diffusion layer is formed tends to be easily reduced. There exists a tendency for the discharge property by the inkjet system of a composition to improve more.

(Phosphorus-containing silicon oxide particles)
Inorganic particles containing a donor element are particles containing phosphorus-containing silicon oxide, which is a reaction product of silicon alkoxide and phosphorus compound, thereby suppressing the formation of an impurity diffusion layer in addition to the required region can do. Further, since phosphorus atoms can diffuse in the reaction product, the diffusion performance of the impurity diffusion layer forming composition can be maintained during the thermal diffusion treatment.

This can be considered as follows, for example.
In the phosphorus-containing silicon oxide obtained by reacting silicon alkoxide with a phosphorus compound, it is considered that the structure derived from the phosphorus compound is dispersed in the silica gel matrix. Therefore, it is considered that the properties of the phosphorus compound itself are greatly different. For example, since the volatility of the phosphorus compound itself is suppressed, out-diffusion of the phosphorus compound at a high temperature that forms an impurity diffusion layer in a semiconductor substrate (for example, a silicon substrate) can be suppressed. That is, the impurity diffusion layer can be formed only in a desired region.

  The phosphorus-containing silicon oxide is not particularly limited as long as it is a reaction product obtained by reacting silicon alkoxide with a phosphorus compound. The phosphorus-containing silicon oxide is preferably obtained by reacting silicon alkoxide with a phosphorus compound and then removing at least a part of the unreacted phosphorus compound and the like. Thereby, out diffusion can be more effectively suppressed.

  The silicon alkoxide can be appropriately selected from commonly used compounds without particular limitation as long as it is a compound capable of causing a sol-gel reaction. The sol-gel reaction here means a hydrolysis reaction of a silicate and a condensation reaction of a silanol group. As a result, the reaction forms a three-dimensionally crosslinked silica gel matrix having a silicon-oxygen bond as a repeating unit.

The number of alkoxy groups constituting the silicon alkoxide is not particularly limited as long as it is 1 or more. From the viewpoint of suppressing out diffusion, the number of alkoxy groups is preferably 2 to 4, more preferably 3 to 4, and still more preferably 4.
When the number of alkoxy groups constituting the silicon alkoxide is 3 or less, the silicon alkoxide may further have a substituent selected from a hydrogen atom, a hydroxy group, and a hydrocarbon group so that the valence of the silicon atom is 4. preferable.
The hydrocarbon group may be an aliphatic group or an aromatic group. Of these, an alkyl group having 1 to 10 carbon atoms and an alkenyl group having 2 to 10 carbon atoms are preferable. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a propenyl group, and a butenyl group.

The silicon alkoxide is preferably a tetraalkoxysilane having an alkoxy group having 1 to 10 carbon atoms, and more preferably a tetraalkoxysilane having an alkoxy group having 1 to 4 carbon atoms.
The alkyl group moiety in the alkoxy group may be any of linear, branched and cyclic alkyl groups. Of these, a linear or branched alkyl group is preferable, and a linear alkyl group is more preferable.
Further, the plurality of alkoxy groups of the silicon alkoxide may be the same alkoxy group or different alkoxy groups.

Specific examples of the silicon alkoxide include silicon methoxide (for example, tetramethoxysilane), silicon ethoxide (for example, tetraethoxysilane), silicon propoxide (for example, tetrapropyloxysilane), silicon butoxide (for example, tetrabutoxysilane). ) And the like.
Of these, silicon methoxide and silicon ethoxide are preferably used because of their availability.

The phosphorus compound is not particularly limited as long as it is a compound containing a phosphorus atom and an oxygen atom. Specifically, phosphoric acid, ammonium hydrogenphosphate salt, diphosphorus pentoxide, diphosphorus trioxide, phosphorous acid, phosphonic acid, phosphonous acid, phosphinic acid, phosphine, phosphoric acid ester, phosphorous acid ester, etc. It is preferable that it is at least one selected from the group consisting of these.
The phosphorus compound is more preferably at least one selected from the group consisting of phosphate esters and phosphite esters. Phosphoric esters and phosphites are more likely to form, for example, P—O—Si bonds when the sol-gel reaction proceeds in a mixed state with silicon alkoxide, and the out-diffusion caused by phosphorus compounds is further suppressed. It tends to be easy to be done.

  The phosphate ester is preferably a compound represented by the following general formula (I).

In general formula (I), R ¹ , R ² and R ³ each independently represent an organic group having 1 to 10 carbon atoms or a hydrogen atom, and at least one of R ¹ , R ² and R ³ has a carbon number. 1 to 10 organic groups.
The organic group is not particularly limited as long as it is a group composed of at least a carbon atom and a hydrogen atom. The organic group may be an aliphatic group such as an alkyl group, an alkenyl group, and an alkynyl group, or may be an aromatic group. The aliphatic group may be linear, branched or cyclic, and may further have a substituent. The aromatic group may be either an aromatic hydrocarbon group or an aromatic heterocyclic group, and may further have a substituent.
Examples of the substituent in the aliphatic group and the aromatic group include an alkyl group, an alkenyl group, a hydroxy group, an alkoxy group, and a halogen atom. Examples of the hetero atom in the aromatic heterocyclic group include a nitrogen atom, an oxygen atom, and a sulfur atom.

  The organic group has 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms. Moreover, when the said organic group has a substituent, carbon number including the carbon atom contained in a substituent is 1-10.

Specific examples of the organic group having 1 to 10 carbon atoms include methyl groups, ethyl groups, propyl groups, butyl groups, pentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, and decyl groups. An alkyl group having 10 carbon atoms; an alkenyl group having 2 to 10 carbon atoms such as a propenyl group and a butenyl group; an aryl group having 6 to 10 carbon atoms (for example, a phenyl group, a toluyl group, and a naphthyl group).
Among these, an alkyl group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable.

Further, at least one of R ^{1 to} R ³ in the general formula (I) is an organic group having 1 to 10 carbon atoms, but at least two of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms. It is preferable that all of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms.
When two or more of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms, they may be the same or different from each other.

  The phosphate ester preferably includes at least one selected from the group consisting of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, and tributyl phosphate.

  The phosphite is preferably a compound represented by the following general formula (II).

In the general formula (II), R ¹ , R ² and R ³ each independently represents an organic group having 1 to 10 carbon atoms or a hydrogen atom, and at least one of R ¹ , R ² and R ³ has a carbon number. 1 to 10 organic groups.
The C1-C10 organic group in General formula (II) is synonymous with the organic group in the said general formula (I), and its preferable aspect is also the same.

In addition, at least one of R ^{1 to} R ³ in the general formula (II) is an organic group having 1 to 10 carbon atoms, but at least two of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms. It is preferable that all of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms.
When two or more of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms, they may be the same or different from each other.

  The phosphite preferably contains at least one selected from the group consisting of trimethyl phosphite, triethyl phosphite, tripropyl phosphite, and tributyl phosphite.

The ratio of silicon atoms and phosphorus atoms contained in the phosphorus-containing silicon oxide is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of diffusibility and out-diffusion suppression, the phosphorus atom is preferably 0.1 to 5.0 mol, more preferably 0.5 to 3.0 mol with respect to 1 mol of silicon atom.
When the ratio is 0.1 or more, the diffusion capacity tends to be further improved. Moreover, it exists in the tendency which can suppress an out diffusion more effectively as it is 5.0 or less.
The ratio of silicon atoms to phosphorus atoms contained in the phosphorus-containing silicon oxide can be measured by an ordinary method using an ICP emission spectroscopic analyzer, glow discharge mass spectrometry, or the like.

  The method for producing the phosphorus-containing silicon oxide is not particularly limited as long as the reaction product of the silicon alkoxide and the phosphorus compound can be obtained. For example, a method in which silicon alkoxide and a phosphorus compound are dissolved or dispersed in a solvent, and a catalyst such as an acid or alkali is added as necessary to remove at least a part of the alcohol derived from the solvent and silicon alkoxide. be able to. In such a production method, the sol-gel reaction accompanying the hydrolysis reaction and dehydration reaction of silicon alkoxide proceeds, and the silicon-oxygen bond network (silica gel matrix) contains a phosphorus-containing structure containing a structure derived from a phosphorus compound. Silicon oxide can be obtained.

The solvent is not particularly limited as long as the sol-gel reaction can proceed. Among them, it is preferable that the polymerization precursor produced by the hydrolysis reaction and dehydration reaction of silicon alkoxide can be dissolved.
Specifically, carbonate compounds (ethylene carbonate, propylene carbonate, etc.), heterocyclic compounds (3-methyl-2-oxazolidinone, N-methylpyrrolidone, etc.), cyclic ethers (dioxane, tetrahydrofuran, etc.), chain ethers (diethyl) Ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, etc.), alcohols (methanol, ethanol, isopropanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether) , Polypropylene glycol monoalkyl ether, etc.), polyhydric alcohols (ethylene Recall, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, etc.), nitrile compounds (acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile, etc.), esters (carboxylic esters, phosphate esters, phosphonate esters) ), Aprotic polar solvents (dimethyl sulfoxide, sulfolane, dimethylformamide, dimethylacetamide, etc.), nonpolar hydrocarbon solvents (toluene, xylene, etc.), chlorinated solvents (methylene chloride, ethylene chloride, etc.), water, etc. Can do.
Of these, alcohols such as ethanol and isopropanol, nitrile compounds such as acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, and benzonitrile, and cyclic ethers such as dioxane and tetrahydrofuran are preferable.
These may be used alone or in combination of two or more.

The amount of the solvent used in the production method is preferably 100 parts by mass or less, more preferably 1 to 10 parts by mass with respect to 1 part by mass of silicon alkoxide. Silicon alkoxy de sol by at most 100 parts by mass - tend to decrease the rate of gel reaction can be suppressed.

Moreover, in the said manufacturing method, you may use catalysts, such as an acid and an alkali. By using a catalyst, hydrolysis and dehydration condensation polymerization can be easily controlled.
The alkali is not particularly limited, and can be appropriately selected from alkali metals such as sodium hydroxide and general materials such as ammonia.
Examples of the acid include inorganic protonic acids and organic protonic acids. Examples of the inorganic protonic acid include hydrochloric acid, sulfuric acid, boric acid, nitric acid, perchloric acid, tetrafluoroboric acid, hexafluoroarsenic acid, hydrobromic acid and the like. Examples of the organic protonic acid include acetic acid, oxalic acid, methanesulfonic acid and the like.

When a catalyst is used in the production method, the amount of the catalyst to be used can be appropriately selected depending on the type and the like. For example, it can be 0.0001 mass part-1 mass part with respect to 1 mass part of silicon alkoxide, and it is preferable that it is 0.001-0.1 mass part.
In particular, when an acid is used as the catalyst, the solubility of the sol in the solvent varies depending on the amount of the acid, and therefore it is preferable to adjust the sol so that it has a soluble solubility.

Moreover, in the said manufacturing method, the solution containing a metal salt may be added to the sol solution of a silicon alkoxide, sol-gel reaction may be advanced, and complex oxide may be formed. Examples of the metal salt include halide salts such as nitrates and chloride salts, and sulfates. Examples of the metal include iron, zirconium, and titanium.
Specific examples of the metal salt include iron nitrate, zirconium oxynitrate, titanium chloride, zirconium oxychloride, zirconium oxynitrate, and titanium sulfate.
These may be used alone or in combination of two or more.

  The metal salt solvent is not particularly limited as long as it dissolves the salt. For example, carbonate compounds (ethylene carbonate, propylene carbonate, etc.), heterocyclic compounds (3-methyl-2-oxazolidinone, N-methylpyrrolidone, etc.), cyclic ethers (dioxane, tetrahydrofuran, etc.), chain ethers (diethyl ether, ethylene) Glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, etc.), alcohols (methanol, ethanol, isopropanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol) Monoalkyl ethers), polyhydric alcohols (ethylene glycol) , Propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, etc.), nitrile compounds (acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile, etc.), esters (carboxylic esters, phosphates, phosphonic acids) Esters, etc.), aprotic polar substances (dimethyl sulfoxide, sulfolane, dimethylformamide, dimethylacetamide, etc.), nonpolar solvents (toluene, xylene, etc.), chlorinated solvents (methylene chloride, ethylene chloride, etc.), and water can be used.

  When a metal salt is used in the production method, the amount of the metal salt added can be appropriately selected according to the type of the metal salt. For example, with respect to 1 part by mass of silicon alkoxide, it can be 0.01 to 1 part by mass, and from the viewpoint of diffusibility of the donor element into the substrate, it is 0.02 to 0.1 part by mass. preferable.

The reaction temperature between the silicon alkoxide and the phosphorus compound in the production method can be appropriately selected according to the silicon alkoxide, the phosphorus compound, the solvent, and the like to be used. For example, it is preferably not less than the boiling point of alcohol produced from silicon alkoxide and phosphorus compound, and preferably not less than the boiling points of the alcohol and solvent. Specifically, the temperature is preferably 40 to 500 ° C, and more preferably 100 to 300 ° C.
The reaction may be performed under reduced pressure, and in that case, the reaction temperature can be appropriately selected according to the boiling point of the alcohol or solvent under reduced pressure.

  Moreover, the reaction time of the silicon alkoxide and the phosphorus compound in the production method can be appropriately selected according to the reaction temperature and the like. For example, it can be 10 minutes to 20 hours, and it is preferably 10 minutes to 10 hours from the viewpoint of simplifying the production process.

The ratio of the addition amount of silicon alkoxide and phosphorus compound in the production method is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of diffusibility and out-diffusion suppression, it is preferable to adjust the addition amount of the silicon alkoxide and the phosphorus compound so that the phosphorus atom is 0.1 to 5.0 mol with respect to 1 mol of the silicon atom. It is more preferable to adjust so that it may become -3.0 mol.
When the ratio is 0.1 or more, the diffusion capacity tends to be further improved. Moreover, it exists in the tendency which can suppress an out diffusion more effectively as it is 5.0 or less.

Examples of the shape of the phosphorus-containing silicon oxide particles include a substantially spherical shape, a flat shape, a block shape, a plate shape, and a scale shape. From the viewpoint of application to the substrate and uniform diffusibility when the impurity diffusion layer-forming diffusion layer-forming composition is used, it is preferably approximately spherical, flat, or plate-like.
The particle size of the phosphorus-containing silicon oxide particles is desirably 50 μm or less. When a phosphorus-containing silicon oxide having a particle size of 50 μm or less is used, a smooth coating film is easily obtained. Further, the particle size is more preferably 10 μm or less. The lower limit is not particularly limited, but is preferably 0.01 μm or more.
Here, the particle size of the phosphorus-containing silicon oxide particles represents a volume average particle size and can be measured by a laser scattering diffraction method particle size distribution measuring device or the like.

When the impurity diffusion layer forming composition contains phosphorus-containing silicon oxide particles, the content ratio of the phosphorus-containing silicon oxide particles in the impurity diffusion layer forming composition is preferably 1% by mass to 30% by mass, More preferably, it is 5 mass%-25 mass%.
When the content is 1% by mass or more, sufficient impurity diffusion ability is obtained, and the resistance of the semiconductor substrate on which the impurity diffusion layer is formed tends to be reduced. There exists a tendency for the discharge property by the inkjet system of things to improve more.

(Boron-containing silicon oxide)
Inorganic particles containing acceptor elements are particles containing boron-containing silicon oxide, which is a reaction product of silicon alkoxide and boron compound, thereby preventing the formation of an impurity diffusion layer in addition to the required region can do. Further, since boron atoms can diffuse in the reaction product, the diffusion performance of the impurity diffusion layer forming composition can be maintained during the thermal diffusion treatment.

This can be considered as follows, for example.
In a boron-containing silicon oxide obtained by reacting a silicon alkoxide and a boron compound, it is considered that a structure derived from the boron compound is present in a dispersed manner in a silica gel matrix. Therefore, it is considered that the properties of the boron compound itself are greatly different. For example, since the volatility of the boron compound itself is suppressed, out-diffusion of the boron compound at a high temperature that forms an impurity diffusion layer in a semiconductor substrate (for example, a silicon substrate) can be suppressed. That is, the impurity diffusion layer can be formed only in a desired region.

  The boron-containing silicon oxide is not particularly limited as long as it is a reaction product obtained by reacting silicon alkoxide with a boron compound. The boron-containing silicon oxide is preferably obtained by reacting silicon alkoxide with a boron compound and then removing at least a part of the unreacted boron compound and the like. Thereby, out diffusion can be more effectively suppressed.

  As said silicon alkoxide, it is synonymous with the silicon alkoxide in the term of phosphorus containing silicon oxide particle, and its preferable aspect is also the same.

  The boron compound is not particularly limited as long as it is a compound containing a boron atom and an oxygen atom. Specific examples include boric acid, boron oxide, and boric acid ester, and at least one selected from the group consisting of these is preferable.

Boron oxide is a compound represented by B ₂ O ₃ and may be a crystallized product or a glassy material. Boric acid is a compound represented by H ₃ BO ₃ or B (OH) ₃ . These compounds can be dissolved in water and exist in the form of H ₃ BO ₃ to form a reaction product with silicon alkoxide. Therefore, in addition to boron oxide and boric acid, any compound that dissolves in water to form H ₃ BO ₃ can be used as the boron compound.

  The boron compound is more preferably at least one selected from borate esters. When the sol-gel reaction proceeds in a state where the borate ester is mixed with silicon alkoxide, for example, it tends to form a B—O—Si bond, and the outdiffusion caused by the boron compound tends to be more suppressed. is there.

  The boric acid ester is preferably a compound represented by the following general formula (I).

In general formula (I), R ¹ , R ² and R ³ each independently represent an organic group having 1 to 10 carbon atoms or a hydrogen atom, and at least one of R ¹ , R ² and R ³ has a carbon number. 1 to 10 organic groups.
The organic group is not particularly limited as long as it is a group composed of at least a carbon atom and a hydrogen atom. The organic group may be an aliphatic group such as an alkyl group, an alkenyl group, and an alkynyl group, or may be an aromatic group. The aliphatic group may be linear, branched or cyclic, and may further have a substituent. The aromatic group may be either an aromatic hydrocarbon group or an aromatic heterocyclic group, and may further have a substituent.
Examples of the substituent in the aliphatic group and the aromatic group include an alkyl group, an alkenyl group, a hydroxy group, an alkoxy group, and a halogen atom. Examples of the hetero atom in the aromatic heterocyclic group include a nitrogen atom, an oxygen atom, and a sulfur atom.

  The organic group has 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms. Moreover, when the said organic group has a substituent, carbon number including the carbon atom contained in a substituent is 1-10.

Specific examples of the organic group having 1 to 10 carbon atoms include methyl groups, ethyl groups, propyl groups, butyl groups, pentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, and decyl groups. An alkyl group having 10 carbon atoms; an alkenyl group having 2 to 10 carbon atoms such as a propenyl group and a butenyl group; an aryl group having 6 to 10 carbon atoms (for example, a phenyl group, a toluyl group, and a naphthyl group).
Among these, an alkyl group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable.

Further, at least one of R ^{1 to} R ³ in the general formula (I) is an organic group having 1 to 10 carbon atoms, but at least two of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms. It is preferable that all of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms.
When two or more of R ^{1 to} R ³ are organic groups having 1 to 10 carbon atoms, they may be the same or different from each other.

  The boric acid ester preferably includes at least one selected from the group consisting of trimethyl borate, triethyl borate, tripropyl borate, and tributyl borate.

The ratio of silicon atoms and boron atoms contained in the boron-containing silicon oxide is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of diffusibility and out-diffusion suppression, the boron atom is preferably 0.1 to 5.0 mol, more preferably 0.2 to 3.0 mol, with respect to 1 mol of the silicon atom.
When the ratio is 0.1 or more, the diffusion capacity tends to be further improved. Moreover, it exists in the tendency which can suppress an out diffusion more effectively as it is 5.0 or less.
The ratio of silicon atoms to boron atoms contained in the boron-containing silicon oxide can be measured by a conventional method using an ICP emission spectroscopic analyzer, glow discharge mass spectrometry, or the like.

  The method for producing the boron-containing silicon oxide is not particularly limited as long as the reaction product of the silicon alkoxide and the boron compound can be obtained. For example, the manufacturing method similar to the method for obtaining the reaction product of the silicon alkoxide and the phosphorus compound described above can be mentioned.

Examples of the shape of the boron-containing silicon oxide particles include a substantially spherical shape, a flat shape, a block shape, a plate shape, and a scale shape. From the viewpoint of application to the substrate and uniform diffusibility when the impurity diffusion layer-forming diffusion layer-forming composition is used, it is preferably approximately spherical, flat, or plate-like.
The particle size of the boron-containing silicon oxide particles is desirably 50 μm or less. When a phosphorus-containing silicon oxide having a particle size of 50 μm or less is used, a smooth coating film is easily obtained. Further, the particle size is more preferably 10 μm or less. The lower limit is not particularly limited, but is preferably 0.01 μm or more.
Here, the particle size of the boron-containing silicon oxide particles represents a volume average particle size, and can be measured by a laser scattering diffraction particle size distribution measuring device or the like.

When the impurity diffusion layer forming composition contains boron-containing silicon oxide particles, the content ratio of the boron-containing silicon oxide particles in the impurity diffusion layer forming composition is preferably 1% by mass to 30% by mass, More preferably, it is 5 mass%-25 mass%.
When the content is 1% by mass or more, sufficient impurity diffusion ability is obtained, and the resistance of the semiconductor substrate on which the impurity diffusion layer is formed tends to be reduced. There exists a tendency for the discharge property by the inkjet system of things to improve more.

  The content ratio of the specific inorganic particles containing a donor element or the specific inorganic particles containing an acceptor element in the impurity diffusion layer forming composition is determined in consideration of dischargeability, diffusibility, and the like in the ink jet system. In general, the content of the specific inorganic particles containing a donor element or the specific inorganic particles containing an acceptor element in the impurity diffusion layer forming composition is preferably 1% by mass or more and 30% by mass or less, preferably 5% by mass. More preferably, it is 25 mass% or less.

The impurity diffusion layer forming composition contains at least one kind of specific inorganic particles containing a donor element or at least one kind of specific inorganic particles containing an acceptor element, and contains the specific inorganic particles and acceptor containing a donor element. It is preferable that only one of the specific inorganic particles containing an element is included.
When the impurity diffusion layer forming composition contains specific inorganic particles containing a donor element, the total content of each of the acceptor elements B, Al, Ga, Tl, and In is preferably 1% by mass or less. . When the content is 1% by mass or less, the donor element is sufficiently diffused.
Moreover, when the said impurity diffusion layer forming composition contains the specific inorganic particle containing an acceptor element, it is preferable that the total content rate of each element of P, Sb, As, and Bi which is a donor element is 1 mass% or less. When the content is 1% by mass or less, the acceptor element is sufficiently diffused.

  The impurity diffusion layer forming composition of the present invention is Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, The total content of Ta, W, Re, Os, Ir, Pt and Au is preferably less than 1% by mass. These elements have empty 3d or 4d orbitals and may act as lifetime killer elements. That is, since the lifetime of minority carriers in the semiconductor is reduced, there is a possibility that the semiconductor performance is deteriorated.

  The impurity diffusion layer forming composition contains a dispersion medium. The dispersion medium is a medium in which specific inorganic particles containing the donor element or specific inorganic particles containing an acceptor element are dispersed in the impurity diffusion layer forming composition. Specifically, the dispersion medium includes a liquid such as water and an organic solvent and a binder such as a water-soluble polymer compound.

The dispersion medium in the impurity diffusion layer forming composition preferably contains at least one selected from water and an organic solvent.
Specific examples of the organic solvent include the same solvents as those exemplified as the dispersion medium in the above-described pulverization treatment of boron nitride particles.
Among these dispersion media, water, alcohol, α-terpineol, diethylene glycol mono-n-butyl ether, and acetic acid diethylene glycol mono-n-butyl ether are preferable from the viewpoint of dischargeability by an ink jet method when a p-type diffusion layer forming composition is used. Water and alcohol are more preferable, and at least water is more preferable.
When the dispersion medium contains an organic solvent, the organic solvent may be used alone or in combination of two or more, or may be a mixed solvent with water.

The dispersion medium in the impurity diffusion layer forming composition preferably contains at least one binder. Examples of the binder include polyvinyl alcohol, polyacrylamides, polyvinylamides, polyvinylpyrrolidone, polyethylene oxides, polysulfonic acid, acrylamide alkylsulfonic acid, cellulose ethers, cellulose derivatives, carboxymethyl cellulose, hydroxyethyl cellulose, ethyl cellulose, gelatin, starch And starch derivatives, sodium alginates, xanthan and xanthan derivatives, gua and gua derivatives, scleroglucan and scleroglucan derivatives, tragacanth and tragacanth derivatives, dextrin derivatives and dextrin derivatives, and (meth) acrylic acid resins, (meth) Acrylic ester resin (eg, alkyl (meth) acrylate resin, dimethylaminoethyl (meth) acrylate Relate resin, etc.), butadiene resin, styrene resin, polyvinyl acetal resin, polyvinyl chloride resin and copolymers thereof, siloxane resin, metal alkoxide, and the like. These are used singly or in combination of two or more.
Among these, at least one selected from polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxides, cellulose derivatives, carboxymethyl cellulose, hydroxyethyl cellulose, gelatin, starch, and starch derivatives, which are water-soluble polymers, from the viewpoint of ejectability by an inkjet method. It is preferable that it contains at least one selected from polyvinyl alcohol, polyvinyl pyrrolidone, and polyethylene oxides.

The molecular weight of the binder is not particularly limited, and it is desirable to adjust appropriately in view of the desired viscosity of the composition. For example, the weight average molecular weight can be 10,000 to 500,000, and preferably 50,000 to 300,000.
The content rate of the binder in the impurity diffusion layer forming composition is not particularly limited, and can be appropriately adjusted in view of a desired viscosity as the composition and dischargeability in the ink jet system. For example, it can be 0.5 mass%-10 mass% in an impurity diffusion layer forming composition, and it is preferable that it is 2 mass%-8 mass%.

  The content ratio of the dispersion medium in the impurity diffusion layer forming composition is appropriately determined in consideration of the ejection stability in the inkjet method, the concentration of the donor element or acceptor element, and the like.

The impurity diffusion layer forming composition may contain various additives, thickeners, wetting agents and the like in addition to the essential components. For example, surfactants, thixotropic agents, inorganic powders, organoboron compounds, organoaluminum compounds and the like can be mentioned.
Among these, it is preferable to include a surfactant and a thixotropic agent.

Examples of the surfactant include nonionic surfactants, cationic surfactants, and anionic surfactants. Nonionic surfactants or cationic surfactants are preferred because impurities such as alkali metals and heavy metals are not brought into the semiconductor device.
Furthermore, examples of nonionic surfactants include silicon surfactants, fluorine surfactants, and hydrocarbon surfactants. However, hydrocarbons are quickly baked during heating such as thermal diffusion treatment. A surfactant is preferred.
From the viewpoint of wettability to the substrate, it is also preferable to use a silicon-based surfactant as the surfactant.

  Examples of the hydrocarbon surfactants include ethylene oxide-propylene oxide block copolymers, acetylene glycol compounds, and the like. An acetylene glycol compound is preferred because the variation in resistance value of the semiconductor device is further reduced.

  When the impurity diffusion layer forming composition contains a surfactant, the content of the surfactant in the impurity diffusion layer forming composition is preferably included so as to have desired liquid properties described later. Specifically, the content of the impurity diffusion layer forming composition is preferably 0.1% by mass to 50% by mass, and more preferably 1% by mass to 20% by mass.

  As thixotropic agents, silica powder, titanium oxide powder, aluminum oxide powder, titanium oxide powder, silicon nitride powder, silicon carbide powder, talc powder, mica powder, glass flake, metal whisker, ceramic whisker, calcium sulfate whisker, asbestos , Smectite and the like, and it is particularly preferable to use silica powder and titanium oxide.

When the impurity diffusion layer forming composition contains a thixotropic agent, the content of the thixotropic agent in the impurity diffusion layer forming composition is preferably included so as to have desired liquid properties described later. Specifically, the content of the impurity diffusion layer forming composition is preferably 0.05% by mass to 10% by mass, and more preferably 0.1% by mass to 5% by mass.
That's right.

Examples of the organoboron compound include organoboron polymers. Any organic boron polymer may be used as long as it contains 10 or more boron atoms in the molecule, and the molecular structure is not particularly limited.
When the said impurity diffusion layer forming composition is comprised including the specific inorganic particle containing a donor element, it is preferable that the content rate of an organoboron compound is 1 mass% or less.

Examples of the organoaluminum compound include AlR ¹ R ² R ³ (wherein R ¹ and R ² are the same or different and represent a hydrocarbon group or a hydrogen atom having 1 to 10 carbon atoms, and R ³ represents 1 to 10 carbon atoms). Wherein R ³ may be the same as or different from the above R ¹ or R ² ). Specifically, trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-t-butylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexyl Aluminum, trioctyl aluminum, diethyl aluminum hydride, di-n-propyl aluminum hydride, di-n-butyl aluminum hydride, diisobutyl aluminum hydride, dihexyl aluminum hydride, diisohexyl aluminum hydride, dioctyl aluminum hydride , Diisooctylaluminum hydride, ethylaluminum dihydride, n-propylaluminum dihydride, isobutylal Such as chloride dihydride and the like.

Although the viscosity at 25 ° C. of the impurity diffusion layer forming composition is 0.1 mPa · s to 500 mPa · s, it is preferably 1 mPa · s to 100 mPa · s from the viewpoint of ejection stability.
When the viscosity at 25 ° C. is out of the above range, there are cases in which the ejection properties in the ink jet method cannot be sufficiently obtained.
The viscosity of the impurity diffusion layer forming composition is measured at 25 ° C. using a B-type viscometer, an E-type viscometer or the like.

  The method of setting the viscosity of the impurity diffusion layer forming composition in the above range can be appropriately selected from commonly used methods. For example, a method for adjusting the content of specific inorganic particles containing a donor element and a specific inorganic particle containing an acceptor element, a method for appropriately selecting the configuration of a dispersion medium, a method for adding a thixotropic agent or a surfactant, etc. be able to.

Moreover, the surface tension at 25 ° C. of the impurity diffusion layer forming composition is preferably 1 mN / m to 200 mN / m, more preferably 5 mN / m to 100 mN / m from the viewpoint of ejection stability.
When the surface tension at 25 ° C. is within the above range, the ejection stability in the ink jet system is further improved, and a pattern with higher accuracy can be formed.
The surface tension of the impurity diffusion layer forming composition is measured at 25 ° C. using a commonly used surface tension meter.

  The method for setting the surface tension of the impurity diffusion layer forming composition in the above range can be appropriately selected from commonly used methods. For example, a method for adjusting the content of specific inorganic particles containing a donor element and a specific inorganic particle containing an acceptor element, a method for appropriately selecting the configuration of a dispersion medium, a method for adding a thixotropic agent or a surfactant, etc. be able to.

The impurity diffusion layer forming composition (hereinafter also simply referred to as “composition”) is applied onto a semiconductor substrate by an inkjet method. As the ink jet method, a known method can be appropriately selected and used. Specifically, a piezoelectric method that discharges the composition using the vibration pressure of the piezoelectric element, a thermal ink jet method that uses the pressure generated by heating the composition to form bubbles, and converts an electrical signal into an acoustic beam. Examples thereof include an acoustic ink jet method in which the composition is irradiated and the composition is discharged using radiation pressure, and a charge control method in which the composition is discharged using electrostatic attraction. Among them, the piezo method is preferable from the viewpoint that a rapid temperature change does not occur in the composition.
As an inkjet apparatus used for an inkjet system, it can select from the normally used thing suitably, and a commercially available inkjet apparatus may be used. The nozzle diameter of the head provided in the ink jet apparatus can be appropriately selected according to the configuration of the impurity diffusion layer forming composition, the pattern to be formed, and the like.

The shape of the pattern (composition layer) formed on the semiconductor substrate can be appropriately selected according to the purpose by the impurity diffusion layer forming composition. For example, when forming a linear pattern, the line width is preferably 10 μm to 100 μm, and more preferably 30 μm to 50 μm.
Since the line width of the pattern to be formed is 10 μm to 100 μm, the width of the impurity diffusion layer formed by the thermal diffusion process becomes approximately 10 μm to 100 μm, and the width of the electrode material formed on the impurity diffusion layer can be controlled. It tends to be easy.
The thickness of the pattern (composition layer) is appropriately selected according to the composition of the impurity diffusion layer forming composition. For example, it can be set to 0.5 μm to 20 μm.

<Method for producing impurity diffusion layer and solar cell element>
Next, a method for manufacturing an n-type diffusion layer, a method for manufacturing a p-type diffusion layer, and a method for manufacturing a solar cell element will be described.

(Manufacturing method of n-type diffusion layer and solar cell element)
A method for producing an n-type diffusion layer as an impurity diffusion layer and a method for producing a solar cell element of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view conceptually showing an example of the manufacturing process of the solar cell element of the present invention. In the subsequent drawings, common constituent elements are denoted by the same reference numerals.

In FIG. 1A, an alkaline solution is applied to a silicon substrate which is a p-type semiconductor substrate 10 to remove a damaged layer, and a texture structure is obtained by etching.
Specifically, the damaged layer on the silicon surface generated when slicing from the ingot is removed with 20% by mass caustic soda. Next, etching is performed with a mixed liquid of 1% by mass caustic soda and 10% by mass isopropyl alcohol to form a texture structure (not shown). In the solar cell element, by forming a texture structure on the light receiving surface (surface) side, a light confinement effect is promoted, and high efficiency is achieved.

In FIG. 1 (2), the n-type diffusion layer forming composition 11 is applied to the surface of the p-type semiconductor substrate 10, that is, the light-receiving surface by an ink jet method, and the n-type diffusion layer forming composition layer 11 is p-type. A pattern is formed on the semiconductor substrate 10. The ink jet method is not particularly limited, and is appropriately selected from commonly used ink jet methods.
Is not particularly limited as coated amount of the n-type diffusion layer forming composition, for example, be a 0.01g ^{/ m 2} ~100g ^/ m 2 as the amount of glass particles, 0.1 g ^/ m 2 to 10 g / M ² is preferable.

The shape of the n-type diffusion layer forming composition layer 11 formed on the p-type semiconductor substrate 10 is not particularly limited and can be appropriately selected depending on the purpose. For example, a linear pattern can be formed, and the line width is preferably 10 μm to 100 μm, and more preferably 30 μm to 50 μm. By using the n-type diffusion layer forming composition to form the n-type diffusion layer forming composition layer 11 with such a line width, the line width of the n-type diffusion layer formed by the thermal diffusion treatment described later is n-type. The line width is approximately the same as the line width of the diffusion layer forming composition layer 11. This facilitates control of the line width of the electrode when forming the electrode on the n-type diffusion layer.
Moreover, a desired pattern can be formed with high accuracy and high productivity by applying the n-type diffusion layer forming composition onto the p-type semiconductor substrate by an inkjet method.

  Depending on the composition of the n-type diffusion layer forming composition, a drying step for volatilizing the solvent contained in the composition may be necessary after coating. In this case, drying is performed at a temperature of about 80 ° C. to 300 ° C. for 1 minute to 10 minutes when a hot plate is used, and about 10 minutes to 30 minutes when a dryer or the like is used. The drying conditions depend on the solvent composition of the n-type diffusion layer forming composition, and are not particularly limited to the above conditions in the present invention.

Next, the p-type semiconductor substrate 10 on which the n-type diffusion layer forming composition 11 is formed is subjected to thermal diffusion treatment at, for example, 600 ° C. to 1250 ° C., preferably 800 ° C. to 1000 ° C. When the temperature is 600 ° C. or higher, impurities are sufficiently diffused and a sufficient BSF effect is obtained. Moreover, deterioration of a semiconductor substrate can be suppressed as it is 1250 degrees C or less.
By this thermal diffusion treatment, the donor element diffuses into the p-type semiconductor substrate as shown in FIG. 1 (3), and the n-type diffusion layer 12 is formed. A known continuous furnace, batch furnace, or the like can be applied to the heat treatment. The furnace atmosphere at the time of the thermal diffusion treatment can be appropriately adjusted with air, oxygen, nitrogen or the like. In particular, the oxygen ratio is preferably less than 5% by volume.

The thermal diffusion treatment time can be appropriately selected according to the content of the donor element contained in the n-type diffusion layer forming composition. For example, it can be 1 minute to 60 minutes, and it is more preferably 2 minutes to 30 minutes.
The diffusion treatment can also be performed using a short-time heat treatment (RTP) technique.

  Since a glass layer (not shown) such as phosphate glass is formed on the surface of the formed n-type diffusion layer 12, this phosphate glass is removed 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.

In the method for producing an n-type diffusion layer of the present invention in which the n-type diffusion layer 12 is formed using the n-type diffusion layer forming composition shown in FIGS. 1 (2) and (3), the n-type diffusion layer 12 is formed at a desired site. The diffusion layer 12 is formed, and an unnecessary n-type diffusion layer is not formed on the back surface or the side surface.
Therefore, in the conventional method of forming an n-type diffusion layer by a gas phase reaction method, a side etching process for removing an unnecessary n-type diffusion layer formed on a side surface is essential. According to the manufacturing method of the invention, the side etching process is not required, and the process is simplified.

When the manufacturing method of the present invention is used, the manufacturing method of the p ⁺ -type diffusion layer (high-concentration electric field layer) 14 on the back surface is limited to a method by conversion from an n-type diffusion layer by aluminum to a p ⁺ -type diffusion layer. However, either method can be adopted, and the choice of manufacturing method is expanded.
As will be described later, the material used for the back surface electrode 20 is not limited to Group 13 aluminum, and for example, Ag (silver), Cu (copper), or the like can be applied. In addition, it can be formed thinner than the conventional one.

In FIG. 1 (4), an antireflection film 16 is formed on the n-type diffusion layer 12. The antireflection film 16 is formed by applying a known technique. For example, when the antireflection film 16 is a silicon nitride film, it is formed by a plasma CVD method using a mixed gas of SiH ₄ and NH ₃ as a raw material. At this time, hydrogen diffuses into the crystal, and orbits that do not contribute to the bonding of silicon atoms, that is, dangling bonds and hydrogen are combined to inactivate defects (hydrogen passivation).
More specifically, the mixed gas flow rate ratio NH ₃ / SiH ₄ is 0.05 to 1.0, the reaction chamber pressure is 13.3 Pa (0.1 Torr) to 266.6 Pa (2 Torr), It is formed under conditions where the temperature is 300 ° C. to 550 ° C. and the frequency for plasma discharge is 100 kHz or more.

  In FIG. 1 (5), the surface electrode 18 is formed on the antireflection film 16 on the surface (light-receiving surface) by printing and drying the surface electrode metal paste by screen printing. The metal paste for a surface electrode contains (1) metal particles and (2) glass particles as essential components, and includes (3) a resin binder and (4) other additives as necessary.

  Next, the back electrode 20 is also formed on the high-concentration electric field layer 14 on the back surface. As described above, in the present invention, the material and forming method of the back electrode 20 are not particularly limited. For example, the back electrode 20 may be formed by applying and drying a back electrode paste containing a metal such as aluminum, silver, or copper. At this time, a silver paste for forming a silver electrode may be partially provided on the back surface for connection between elements in the module process.

  In FIG. 1 (6), an electrode is baked and a solar cell element is completed. When firing at a temperature of 600 ° C. to 900 ° C. for several seconds to several minutes, the antireflection film 16 that is an insulating film is melted by the glass particles contained in the electrode metal paste on the surface side, and the silicon 10 surface is also partially melted. The metal particles (for example, silver particles) in the paste form a contact portion with the silicon substrate 10 and solidify. Thereby, the formed surface electrode 18 and the silicon substrate 10 are electrically connected. This is called fire-through.

  Next, the shape of the surface electrode 18 will be described. The surface electrode 18 includes a bus bar electrode 30 and finger electrodes 32 intersecting with the bus bar electrode 30. FIG. 2A is a plan view of a solar cell element in which the surface electrode 18 includes a bus bar electrode 30 and a finger electrode 32 intersecting with the bus bar electrode 30 as viewed from the surface. FIG. 2B is an enlarged perspective view illustrating a part of FIG.

  Such a surface electrode 18 can be formed by means such as screen printing of the above-described electrode metal paste, plating of the electrode material, vapor deposition of the electrode material by electron beam heating in a high vacuum, or the like. The surface electrode 18 composed of the bus bar electrode 30 and the finger electrode 32 is generally used as an electrode on the light receiving surface side and is well known, and it is possible to apply known forming means for the bus bar electrode and finger electrode on the light receiving surface side. it can.

(First p-type diffusion layer manufacturing method)
A first manufacturing method for forming a p-type diffusion layer as an impurity diffusion layer on a semiconductor substrate (preferably a silicon substrate) is the above-described n-type diffusion layer manufacturing method, wherein the n-type diffusion layer forming composition is used as a p-type diffusion layer. In this method, the n-type diffusion layer is replaced with the p ⁺ -type diffusion layer and applied to the forming composition.
That is, in FIG. 1 (2), the n-type diffusion layer forming composition is applied to form the n-type diffusion layer forming composition layer 11, and the thermal diffusion treatment is performed to obtain the n-type shown in FIG. 1 (3). Similarly to the formation of the diffusion layer 12, the p-type diffusion layer forming composition described above is applied to form the p-type diffusion layer forming composition layer 13, and a thermal diffusion treatment is performed, so that FIG. The p ⁺ type diffusion layer 14 shown in FIG.

In this manufacturing method, after the n-type diffusion layer forming composition layer 11 and the p-type diffusion layer forming composition layer 13 are formed, a thermal diffusion process is performed to form the n-type diffusion layer 12 and the p-type diffusion layer 14. Is preferred. By this thermal diffusion treatment, the donor element diffuses into the p-type semiconductor substrate on the front surface to form the n-type diffusion layer 12, and the acceptor element diffuses on the back surface to form the p ⁺ -type diffusion layer 14. Except for this step, the solar cell element is manufactured by the same steps as the method for manufacturing the n-type diffusion layer.

(Method for producing second p-type diffusion layer)
In the second method for producing a p-type diffusion layer, a method for converting an n-type diffusion layer formed also on the back surface to a p ⁺ diffusion layer with a mixed gas containing phosphorus oxychloride (POCl ₃ ) will be described.
In the following, a method of forming a p ⁺ -type diffusion layer on a p-type semiconductor substrate will be exemplified, but a method of forming a p-type diffusion layer on an n-type semiconductor substrate can be similarly applied.

  First, an alkaline solution is applied to a silicon substrate which is a p-type semiconductor substrate to remove a damaged layer, and a texture structure is obtained by etching. This process is the same as that described with reference to FIG. 1A in the formation of the n-type diffusion layer.

Next, several tens of minutes of treatment is performed at 800 ° C. to 900 ° C. in a mixed gas atmosphere of phosphorus oxychloride (POCl ₃ ), nitrogen, and oxygen to form an n-type diffusion layer uniformly on the substrate. At this time, in the method using the phosphorus oxychloride atmosphere, the diffusion of phosphorus extends to the side surface and the back surface, and the n-type diffusion layer is formed not only on the surface but also on the side surface and the back surface. Therefore, a side etching process is performed in order to remove the side n-type diffusion layer.

  Then, the p-type diffusion layer forming composition is applied onto the n-type diffusion layer on the back surface of the p-type semiconductor substrate, that is, the surface that is not the light receiving surface. In the present invention, the coating method is not limited, and examples thereof include a printing method, a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method.

The p-type is not particularly limited as coating amount of the diffusion layer forming composition, for example, be a 0.01g ^/ cm ² ~100g ^/ cm 2 as amount of glass particles, 0.05g ^/ cm 2 ~10g ^/ it is preferably cm ^{2, and} is preferably ^{0.1g / m 2 ~10g / m 2} . As the coating amount increases, the diffusion of the acceptor element into the semiconductor substrate tends to become easier.

  Depending on the composition of the p-type diffusion layer forming composition, it may be preferable to provide a drying step for volatilizing the solvent contained in the composition after coating. In this case, drying is performed at a temperature of about 80 ° C. to 300 ° C. for 1 minute to 10 minutes when a hot plate is used, and about 10 minutes to 30 minutes when a dryer or the like is used. The drying conditions can be appropriately selected depending on the solvent composition of the n-type diffusion layer forming composition, and are not particularly limited to the above conditions in the present invention.

The semiconductor substrate coated with the p-type diffusion layer forming composition is subjected to thermal diffusion treatment at, for example, 600 ° C. or higher, preferably 800 ° C. or higher. As an upper limit temperature of a thermal diffusion process, it is preferable that it is 1250 degrees C or less, for example, and it is more preferable that it is 1000 degrees C or less. By this thermal diffusion treatment, the acceptor element diffuses into the semiconductor substrate, and a p ⁺ -type diffusion layer is formed. A known continuous furnace, batch furnace, or the like can be applied to the heat treatment. The thermal diffusion atmosphere preferably has an oxygen ratio of less than 5% by volume.
When the heat treatment temperature is 600 ° C. or higher, the acceptor element is sufficiently diffused and a sufficient BSF effect is obtained. Moreover, it can suppress that a board | substrate deteriorates that it is 1250 degrees C or less.

The thermal diffusion treatment time can be appropriately selected according to the content of the acceptor element contained in the p-type diffusion layer forming composition. For example, it can be 1 minute to 60 minutes, and it is more preferably 2 minutes to 30 minutes.
The heat treatment for forming the diffusion layer can also be performed using a short time heat treatment (RTP) technique.

  Then, after removing the glass by etching, an antireflection film is formed on the formed n-type diffusion layer. This step is the same as that described with reference to FIG. 1 (4) in the formation of the n-type diffusion layer.

  On the antireflection film on the surface (light receiving surface), the surface electrode metal paste is printed, applied and dried by a screen printing method to form a surface electrode. This step is the same as that described with reference to FIG. 1 (5) in the formation of the n-type diffusion layer.

Next, a back electrode is also formed on the p ⁺ -type diffusion layer on the back surface. The back electrode formation process is also the same as that described for the n-type diffusion layer.

  The electrode is fired to complete the solar cell element. This process is the same as that described with reference to FIG. 1 (6) in the formation of the n-type diffusion layer.

  Since a glass layer is formed on the surface of the p-type diffusion layer, the glass is removed 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.

(Manufacturing method of other forms of n-type diffusion layer and p-type diffusion layer)
In the above description, the solar cell element in which the n-type diffusion layer is formed on the front surface, the p ⁺ -type diffusion layer is formed on the back surface, and the front surface electrode and the back surface electrode are further provided on the respective layers has been described. If the layer forming composition and the p-type diffusion layer forming composition are used, it is also possible to produce a back contact type solar cell element.

The back contact type solar cell element has all electrodes provided on the back surface to increase the area of the light receiving surface. That is, in the back contact type solar cell element, it is necessary to form both the n-type diffusion region and the p ⁺ -type diffusion region on the back surface to form a pn junction structure. The n-type diffusion layer forming composition and the p-type diffusion layer forming composition of the present invention can form an n-type diffusion site and a p-type diffusion layer site at a specific site, and thus a back contact solar cell It can be suitably applied to the manufacture of elements.

  Specifically, for example, a back contact type solar cell element can be manufactured by a manufacturing method including a manufacturing process as schematically shown in FIG.

A p-type diffusion layer forming composition and an n-type diffusion layer forming composition are applied to the surface of the p-type semiconductor substrate 1 by an inkjet method so that each forms a desired pattern. Subsequently, the p ⁺ type diffusion layer 3 and the n type diffusion layer 6 can be formed in specific regions by subjecting this to thermal diffusion treatment.
As shown in FIG. 3A by the thermal diffusion treatment, a heat-treated material layer 2 of a p-type diffusion layer forming composition is formed on the p ⁺ -type diffusion layer 3 of the p-type semiconductor substrate 1 to form an n-type diffusion layer. A heat-treated product layer 5 of an n-type diffusion layer forming composition is formed on 6.

Next, the heat-treated product layer 2 of the p-type diffusion layer forming composition formed on the p ⁺ -type diffusion layer 3 and the heat-treated product of the n-type diffusion layer forming composition formed on the n-type diffusion layer 6 Layer 5 is removed by etching or the like.
As a result, as shown in FIG. 3B, the heat-treated product layer 2 of the p-type diffusion layer forming composition and the heat-treated product layer 5 of the n-type diffusion layer forming composition in FIG. Thus, the p-type semiconductor substrate 1 in which the p ⁺ -type diffusion layer 3 and the n-type diffusion layer 6 are selectively formed is obtained.

Next, a reflective film or surface protective film 7 is formed on the p-type semiconductor substrate 1 by a conventional method. At this time, as shown in FIG. 3C1, a reflective film or a surface protective film 7 may be partially formed so that the p ⁺ -type diffusion layer 3 and the n-type diffusion layer 6 are exposed on the surface.
Further, as shown in FIG. 3C2, a reflective film or a surface protective film 7 may be formed on the entire surface of the p-type semiconductor substrate 1.

Next, an electrode metal paste is selectively applied on the p ⁺ -type diffusion layer 3 and the n-type diffusion layer 6 and heat-treated, so that the p ⁺ -type diffusion layer 3 and the n-type are formed as shown in FIG. On the diffusion layer 6, the electrode 4 and the electrode 8 can be formed, respectively.
When a reflective film or a surface protective film is formed on the entire surface of the p-type semiconductor substrate 1 as shown in FIG. 3 (c2), the electrode paste containing a glass powder having fire-through property can be used. As shown in FIG. 3D, the electrode 4 and the electrode 8 can be formed on the p ⁺ -type diffusion layer 3 and the n-type diffusion layer 6, respectively.

  In the solar cell element manufactured by the manufacturing method including the manufacturing process shown in FIG. 3, since no electrode exists on the light receiving surface, sunlight can be taken in effectively.

In the production of the back-contact solar cell element described above, the has been described the case of using a p-type semiconductor substrate, in the same manner by using the n-type semiconductor substrate, it is possible to produce a solar cell element.

<Solar cell>
The solar cell of the present invention includes at least one of the solar cell elements, and is configured by arranging tab wires on the electrodes of the solar cell element. If necessary, the solar cell may be configured by connecting a plurality of solar cell elements via tab wires and further sealing with a sealing material.
The tab wire and the sealing material are not particularly limited, and can be appropriately selected from those usually used in the art.
In this specification, the solar cell element means one having a silicon substrate on which a pn junction is formed and an electrode formed on the silicon substrate. In addition, the solar cell is a state in which a tab wire is provided on the electrode of the solar cell element, and a plurality of solar cell elements are connected via the tab line as necessary and sealed with a sealing resin or the like. Means things.

  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 stated, all chemicals used were reagents. “%” Means “% by mass” unless otherwise specified.

<Example 1>
(Preparation of Impurity Diffusion Layer-Forming Composition 1)
Polyvinyl alcohol (molecular weight 10,000, partially saponified type, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in water to prepare a 10% polyvinyl alcohol aqueous solution. 8 g of this solution, 1.5 g of hexagonal boron nitride (manufactured by Wako Pure Chemical Industries, reagent grade, volume average particle size: 12 μm), fumed silica (R200 manufactured by Nippon Aerosil), surfactant SH28PA (silicone-based surface activity) An impurity diffusion layer forming composition 1 was prepared by mixing 0.2 g of an agent, Toray Dow Corning Silicone Co., Ltd.) with an automatic mortar kneader.
The viscosity (25 ° C.) of the impurity diffusion layer forming composition 1 was 17 mPa · s. The viscosity of the impurity diffusion layer forming composition was measured at 25 ° C. by an ordinary method using an E-type viscometer.

(Thermal diffusion and etching process)
On the surface of the sliced n-type silicon substrate (hereinafter also referred to as “n-type sliced silicon substrate”), the impurity diffusion layer forming composition 1 is lined at 50 μm and 40 mm in length using an inkjet apparatus (manufactured by Epson Corporation). It gave so that it might become a linear pattern. Subsequently, it was dried on a hot plate at 150 ° C. for 5 minutes to form an impurity diffusion layer forming composition layer having a film thickness of 11 μm. Subsequently, heat treatment was performed for 1 minute in a 600 ° C. annular furnace in which air was flowed at 5 L / min. Next, nitrogen gas was supplied at 5 L / min. Thermal diffusion treatment was performed for 20 minutes in a tunnel furnace at 950 ° C. that was flowed in
After cooling, the n-type silicon substrate is washed with running water to remove the glass layer formed on the surface of the n-type silicon substrate. The substrate is immersed in a 2.5% HF aqueous solution for 5 minutes, and then washed with running water, ultrasonic Cleaning and drying were performed to obtain an n-type slice silicon substrate on which an impurity diffusion layer (p-type diffusion layer) was formed.

[Evaluation]
(Sheet resistance measurement)
The sheet resistance of the region where the p-type diffusion layer was formed on the surface of the obtained n-type slice silicon substrate was measured by a four-probe method using a Loresta-EP MCP-T360 type low resistivity meter manufactured by Mitsubishi Chemical Corporation. It was measured.
The portion to which the impurity diffusion layer forming composition 1 was applied was 120Ω / □, and B (boron) was diffused to form a p-type diffusion layer.
On the other hand, the sheet resistance of the non-application region at a position 5 mm away from the region to which the impurity diffusion layer forming composition 1 is applied is 1000Ω / □ or more, and an impurity diffusion layer (p-type diffusion layer) is substantially formed. It was judged that it was not.

  Further, no warpage occurred in the n-type slice silicon substrate on which the p-type diffusion layer obtained above was formed. Further, when the surface of the n-type slice silicon substrate was observed with an optical microscope and a scanning electron microscope, no difference was observed between the portion coated with the paste containing boron nitride and the portion not coated.

<Example 2>
(Preparation of glass particles)
SiO ₂ (manufactured by Wako Pure Chemical Industries, Ltd.), P ₂ O ₅ (manufactured by Wako Pure Chemical Industries, Ltd.), CaCO ₃ (manufactured by Wako Pure Chemical Industries, Ltd.) are used as raw materials, and the respective molar ratios are SiO ₂ : P ₂ O ₅ : CaO. = 30:60:10, mixed in an alumina crucible, heated to 1400 ° C at 400 ° C / h, held for 1 hour, and then rapidly cooled. This was pulverized using an automatic mortar kneader to obtain glass particles containing a donor element.
When the powder X-ray diffraction (XRD) pattern of the obtained glass particles was measured with an X-ray diffractometer (RINT-2000, manufactured by Rigaku Corporation) using Cu-Kα rays using a Ni filter, the obtained glass particles Was confirmed to be amorphous.
Moreover, it was 8 micrometers when the volume average particle diameter of the glass particle was measured with the laser diffraction type particle size distribution measuring apparatus.

(Preparation of impurity diffusion layer forming composition 2)
Impurity diffusion layer forming composition 2 was prepared in the same manner as in Example 1 except that the SiO ₂ —P ₂ O ₅ —CaO glass was used instead of boron nitride.
The viscosity (25 ° C.) of the impurity diffusion layer forming composition 2 was 19 mPa · s.

(Thermal diffusion and etching process)
Impurity diffusion layer forming composition 2 was applied in the same manner as in Example 1 except that a textured p-type silicon substrate was used instead of the sliced n-type silicon substrate, and then an impurity diffusion layer was formed in the same manner. Thus, a p-type silicon substrate on which an impurity diffusion layer (n-type diffusion layer) was formed was obtained. The obtained p-type silicon substrate was evaluated in the same manner.

The sheet resistance of the region to which the impurity diffusion layer forming composition 2 was applied was 30Ω / □, and P (phosphorus) was diffused to form an impurity diffusion layer (n-type diffusion layer).
On the other hand, the sheet resistance of the non-application region at a position 5 mm away from the region to which the impurity diffusion layer forming composition 2 is applied is 1000Ω / □ or more, and an impurity diffusion layer (n-type diffusion layer) is substantially formed. Determined to be

[Example 3]
(Preparation of glass particles)
SiO ₂ (manufactured by Wako Pure Chemical Industries, Ltd.), B ₂ O ₃ (manufactured by Wako Pure Chemical Industries, Ltd.), ZnO (manufactured by Wako Pure Chemical Industries, Ltd.) were used as raw materials, and the respective molar ratios were SiO ₂ : B ₂ O ₃ : ZnO = The mixture was mixed at 10:40:50, placed in an alumina crucible, heated to 1400 ° C. at 400 ° C./h, held for 1 hour, and then rapidly cooled. This was pulverized using an automatic mortar kneader to obtain glass particles containing an acceptor element.
The powder X-ray diffraction (XRD) pattern of the obtained glass particles was measured with an X-ray diffractometer (RINT-2000, manufactured by Rigaku Corp.) using Cu-Kα rays using a Ni filter. The XRD pattern is shown in FIG. From FIG. 1, it was confirmed that the obtained glass particles were amorphous. Moreover, it was 8 micrometers when the volume average particle diameter of the glass particle was measured with the laser diffraction type particle size distribution measuring apparatus.

(Preparation of Impurity Diffusion Layer-Forming Composition 3)
Impurity diffusion layer forming composition 3 was prepared in the same manner as in Example 1 except that the SiO ₂ —B ₂ O ₃ —ZnO glass was used instead of boron nitride.
The viscosity (25 ° C.) of the impurity diffusion layer forming composition 3 was 18 mPa · s.

(Thermal diffusion and etching process)
Next, an impurity diffusion layer is formed in the same manner as in Example 1 except that the impurity diffusion layer forming composition 3 is used, and an n-type slice silicon substrate on which the impurity diffusion layer (n-type diffusion layer) is formed is obtained. Obtained. The obtained n-type slice silicon substrate was similarly evaluated.

The sheet resistance of the region to which the impurity diffusion layer forming composition 3 was applied was 45Ω / □, and B (boron) diffused to form an impurity diffusion layer (p-type diffusion layer).
On the other hand, the sheet resistance of the non-application region at a position 5 mm away from the region to which the impurity diffusion layer forming composition 3 is applied is 1000Ω / □ or more, and an impurity diffusion layer (p-type diffusion layer) is substantially formed. Determined to be

[Comparative Example 1]
Impurity diffusion layer forming composition C1 was prepared in the same manner as in Example 1 except that B ₂ O ₃ powder (manufactured by High Purity Chemical Laboratory) was used instead of boron nitride. However, in order to dissolve B ₂ O ₃ powder in water, it was stirred at 25 ° C. for 5 minutes.
The viscosity (25 ° C.) of the impurity diffusion layer forming composition C1 was 11 mPa · s.

  Next, an impurity diffusion layer was formed in the same manner as in Example 1 to obtain an n-type slice silicon substrate on which the impurity diffusion layer (n-type diffusion layer) was formed. The obtained n-type slice silicon substrate was similarly evaluated.

The sheet resistance of the region to which the impurity diffusion layer forming composition C1 was applied was 40Ω / □, and B (boron) diffused to form an impurity diffusion layer (p-type diffusion layer).
Moreover, the sheet resistance of the non-application | coating area | region which is 5 mm away from the area | region which provided the impurity diffusion layer forming composition C1 was 180 ohms / square, and the impurity diffusion layer (p-type diffusion layer) was formed.

[Comparative Example 2]
In Example 2, an impurity diffusion layer forming composition C2 was prepared in the same manner as in Example 2 except that P ₂ O ₅ powder was used instead of SiO ₂ —P ₂ O ₅ —CaO glass.
The viscosity (25 ° C.) of the impurity diffusion layer forming composition C2 was 17 mPa · s.

  Next, an impurity diffusion layer was formed in the same manner as in Example 2 to obtain a p-type silicon substrate on which an impurity diffusion layer (n-type diffusion layer) was formed. The obtained p-type silicon substrate was evaluated in the same manner.

The sheet resistance of the region to which the impurity diffusion layer forming composition C2 was applied was 40Ω / □, and P (phosphorus) was diffused to form an impurity diffusion layer (n-type diffusion layer).
On the other hand, the sheet resistance of the non-application area | region which is 5 mm away from the area | region which provided the impurity diffusion layer forming composition C2 was 140 ohms / square, and the impurity diffusion layer (n type diffusion layer) was formed.

  By using the impurity diffusion layer forming composition of the present invention, low sheet resistance can be realized while suppressing formation of an impurity diffusion layer in an unnecessary region (out diffusion).

1 p-type semiconductor substrate 2, 5 heat-treated material layer 3 p ⁺ -type diffusion layer 4, 8 electrode 6 n-type diffusion layer 7 reflective film or surface protective film 10 p-type semiconductor substrate 12 n-type diffusion layer 14 high concentration electric field layer 16 reflection Prevention film 18 Front electrode 20 Back electrode (electrode layer)
30 Busbar electrode 32 Finger electrode

Claims (14)

  Inorganic particles containing at least one donor element selected from the group consisting of glass particles containing a donor element and particles containing a reaction product of silicon alkoxide and a phosphorus compound, or glass particles, boron nitride particles and silicon containing an acceptor element An impurity diffusion layer forming composition for inkjet, comprising inorganic particles containing at least one acceptor element selected from the group consisting of particles containing a reaction product of an alkoxide and a boron compound, and a dispersion medium.   The impurity diffusion layer forming composition according to claim 1, wherein the glass particles containing the donor element contain at least one kind of donor element selected from P (phosphorus) and Sb (antimony). The glass particles containing the donor element include at least one donor element-containing material selected from P ₂ O ₃ , P ₂ O ₅ and Sb ₂ O ₃ , SiO ₂ , K ₂ O, Na ₂ O, Li _2. Or at least one glass component material selected from O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ , and MoO _3. The composition for forming an impurity diffusion layer according to claim 2. The glass particles containing the acceptor element, B (boron), Al (aluminum) and Ga at least one impurity diffusion layers form Narugumi composition as claimed in claim 1 comprising an acceptor element selected from (gallium) . The glass particles containing the acceptor element include at least one acceptor element-containing substance selected from B ₂ O ₃ , Al ₂ O ₃ and Ga ₂ O ₃ , SiO ₂ , K ₂ O, Na ₂ O, Li _2. Or at least one glass component material selected from O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V ₂ O ₅ , SnO, ZrO ₂ , and MoO _3. impurity diffusion layers form Narugumi composition as claimed in claim 4.   The impurity diffusion layer forming composition according to any one of claims 1 to 5, wherein the dispersion medium contains at least one selected from water and an organic solvent.   The impurity diffusion layer forming composition according to claim 1, wherein the dispersion medium contains a water-soluble polymer compound.   The content rate of the inorganic particle containing the said donor element or the inorganic particle containing an acceptor element is 1-30 mass%, The impurity diffusion layer forming composition of any one of Claims 1-7.   Furthermore, the impurity diffusion layer forming composition of any one of Claims 1-8 containing a thixotropic agent.   Furthermore, the impurity diffusion layer forming composition of any one of Claims 1-9 containing surfactant.   A step of discharging the impurity diffusion layer forming composition according to any one of claims 1 to 10 on a semiconductor substrate by an ink jet method to form a patterned composition layer, and the composition layer And a step of diffusing the donor element or the acceptor element into the semiconductor substrate by heat-treating the semiconductor substrate on which is formed.   The method for producing an impurity diffusion layer according to claim 11, wherein the composition layer has a linear pattern and a line width of 10 μm to 100 μm. To claim 11 or claim 12 impurity diffusion layer of the semiconductor substrate formed with the impurity diffusion layer by the manufacturing method of the impurity diffusion layer according to method of manufacturing a solar cell element comprising the step of forming an electrode. On the electrode of the solar cell device manufactured by the manufacturing method of the solar cell element according to claim 13, a method for manufacturing a solar cell comprising a step of placing a tab line.