JP2009170867A - Light generating element and method of manufacturing the light-electricity generating element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a light electricity generating element, which consistently forms a surface electrode layer from a rear-surface electrode layer at a high speed. <P>SOLUTION: The method of manufacturing a light electricity generating element I having a semiconductor layer 3 for generating electricity through light irradiation has: a rear-surface electrode layer forming step of forming a rear-surface electrode layer 2 on a substrate 1 made of glass; a precursor layer forming step of forming a semiconductor precursor layer 8 on the rear-surface electrode layer 2, the precursor layer which is made up of a plurality of layers and which contains a crystal type of elements different from a crystal type of elements forming the semiconductor layer 3; a front surface electrode layer forming step of forming a front surface electrode layer 5 on the formed semiconductor precursor layer 8; and a precursor layer diffusing step of forming a semiconductor crystal by heating the semiconductor precursor layer 8 after the rear-surface electrode layer forming step, the precursor layer forming step, and the front-surface electrode layer forming step. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a photovoltaic device, and more particularly to a method for manufacturing a photovoltaic device that generates voltage and current by receiving light.

In recent years, as a part of global warming countermeasures, expectations for solar cells are increasing. In particular, CIS solar cells using chalcopyrite type compound semiconductors centered on CuInSe ₂ are attracting attention because of their high photoelectric conversion efficiency, long-term stability, and relatively low cost. Have started.

First, a CIS solar cell will be described with reference to the drawings. FIG. 14 is a diagram illustrating the structure of a general CIS solar cell. As shown in FIG. 14, a general CIS solar cell has a structure in which a back electrode layer 2, an absorption layer 3 </ b> A, a buffer layer 4, and a surface electrode layer 5 are laminated on a substrate 1. As the substrate 1, stainless steel foil or the like is used in addition to glass. A Mo thin film is used for the back electrode layer 2 and a CuInSe-based chalcopyrite compound semiconductor is used for the absorption layer 3A. The absorption layer 3A has an optimized band gap so that it can easily absorb sunlight. Usually, Cu (Ga, In) Se _{2 in} which part of In in CuInSe ₂ is replaced with Ga, or part of Se is used. CuIn (S, Se) ₂ substituted with S is used. Further, a compound having high electrical resistance such as CdS, ZnS, InS or the like is used for the buffer layer 4, and the surface electrode layer 5 is made of ITO (In—Sn—O) or AZO (Al—Zn—) which are transparent electrode materials. O) is used. Further, a comb-shaped electrode 7 for efficiently collecting generated electrons is provided on the front electrode layer 5, and is connected to the positive electrode 6 provided on the back electrode layer 2 by receiving light. A voltage is generated.

Such a CIS solar cell is usually manufactured through the following steps. FIG. 15 is a diagram illustrating a manufacturing process of a general CIS solar cell. As shown in FIG. 15, a back electrode is formed by sputtering on a substrate that has been subjected to pretreatment such as cleaning, and further, copper (Cu), indium (In), and these compounds. The precursor layer which consists of is formed (back surface electrode, precursor layer film-forming process). Next, the substrate is transferred to a heating reactor, and the precursor layer is reacted with selenium in a hydrogen selenide (He ₂ Se) gas (gas phase selenization) while being heated to about 500 ° C., and the CuInSe ₂ absorption layer is formed. To obtain (precursor selenization step). Thereafter, the substrate on which the back electrode and the CuInSe ₂ absorption layer are laminated is transferred to a solution growth tank, and a buffer layer made of CdS, ZnS or the like is formed by a solution growth method (buffer layer formation step). Subsequently, after washing and drying the alkaline aqueous solution attached to the substrate, a surface electrode layer such as ITO or AZO is formed by sputtering using a predetermined sputtering apparatus (surface electrode layer forming step).

Next, the power generation mechanism of the CIS solar cell will be described. The absorption layer 3A is made of polycrystal of a chalcopyrite semiconductor as described above, and is divided into a p-type semiconductor layer 3a and an n-type semiconductor layer 3b. A chalcopyrite type semiconductor having a composition that is normally used is a p-type semiconductor, but a group II element (Cd, Zn, etc.) diffused from the buffer layer 4 enters the Cu site in the absorption layer 3A, thereby It has been found that some become n-type semiconductors.
Thus, the pn junction of the CIS solar cell is a homojunction existing in the absorption layer 3A. Light incident from the surface electrode layer 5 is mainly absorbed by the absorption layer 3A, excites electrons in the depletion layer near the pn junction formation portion, and the generated electrons flow to the surface electrode layer 5 side, while the generated vacancies Generates electricity by flowing to the back electrode layer 2 side.

  As described above, the role of the buffer layer 4 is as follows: 1) supplying the atoms that make the absorption layer 3A n-type, and 2) burying pinholes generated in the absorption layer 3A, Prevent short circuit of the back electrode layer 2, 3) reduce damage to the absorption layer 3A when forming the surface electrode layer 5, and 4) prevent defects between the absorption layer 3A and the surface electrode layer 5. 5) and suppression of band mismatch. Thus, the buffer layer 4 seems indispensable at least in terms of forming a pn junction in the absorption layer 3A, but there is an example in which the power generation operation is caused without using the buffer layer 4 (see Patent Document 1). ).

Among the thin films constituting each layer of the CIS solar cell, various devices have been made particularly as a method for forming the absorbing layer 3A. As such a film forming method, for example, a vacuum deposition method, a vapor phase selenization method, a sputtering method, a hybrid sputtering method, and the like are known (see Patent Documents 2 to 4). Of these, the highest photoelectric conversion efficiency is obtained by the vacuum deposition method.
Further, as a measure for improving the crystallinity of the absorption layer 3A, after forming the absorption layer 3A, a material that becomes a absorption layer 3A or a precursor of the absorption layer 3A using a laser, a high-power lamp, or the like is used. There is known a method of recrystallization by melting (see Patent Documents 5 to 7).
Furthermore, many CIS solar cell manufacturing methods require the use of both a dry process and a wet process, which is a major obstacle to cost reduction. As a measure for solving this problem, a method using an all-dry process has been studied (see Patent Document 1).

Japanese Patent Laid-Open No. 06-045248 JP 2000-087234 A JP 05-326997 A JP 05-263219 A Japanese Patent Application Laid-Open No. 64-026380 JP 09-235172 A Japanese Patent Laid-Open No. 10-079523

By the way, from an industrial viewpoint, development of a process capable of manufacturing a CIS solar cell at a low cost is required. However, all of the conventional manufacturing methods require complicated processes, and thus there is a limit to reducing the cost of solar cells. For example, as described above, in a general CIS solar cell manufacturing process, at least two types of sputtering apparatuses, a heating reaction furnace, and a solution growth tank are required. Moreover, since the use of H ₂ Se gas is toxic gas, it is necessary to toxic gas treatment apparatus and special safety measures. In addition, since an aqueous alkali solution is used in the solution growth method, an alkali treatment facility is required.

Furthermore, in order to improve the performance of the CIS solar cell, a high-quality absorption layer in which lattice defects, precipitation of excess components, generation of heterogeneous compounds, and the like are suppressed is formed, and carriers generated in the depletion layer are formed. It is important to prevent degradation. It is also important to prevent the generation of lattice defects in the absorption layer when forming a homojunction in the absorption layer.
However, for example, the vacuum vapor deposition method, which is one of the methods for forming the absorption layer, does not provide the thin film composition and film thickness uniformity when the film is formed on a large-area substrate. There is a problem that it is sometimes difficult to control the temperature of the substrate. In particular, when forming the absorption layer, it is necessary to accurately maintain the temperature of the substrate at 500 ° C. or higher, and when forming the pn junction, the temperature of the substrate is increased to a low temperature of about 200 ° C. to 300 ° C. Need to hold time. Therefore, in practice, it is difficult to consistently form the back electrode layer, the absorption layer, the pn junction formation layer, and the surface electrode layer on the substrate at a high speed by a vacuum deposition method.

  Next, the vapor phase selenization method requires the use of toxic hydrogen selenide and other gases when selenizing a thin film having a composition that serves as a precursor of the absorption layer, and therefore requires special processing equipment. Become. Further, when selenizing, since it is necessary to expose a thin film having a composition as a precursor to the selenium-containing gas for several tens of minutes to several hours, a long film forming time is required.

  When the sputtering method is used, it is necessary to melt and recrystallize the formed absorption layer. As a result of investigations by the inventors, the crystallinity of the absorption layer was improved by heating the absorption layer after forming each thin film from the back electrode to the front electrode by a conventional sputtering method. However, a pn junction cannot be formed in the absorption layer simultaneously with melting and recrystallization, and it has been extremely difficult to operate as a solar cell. In this case, it is necessary to once remove the layer for protecting the absorption layer during melt crystallization and newly form a buffer layer, a transparent electrode layer, and the like for forming a pn junction.

  In the case of the hybrid sputtering method, since a buffer layer necessary for forming a pn junction is usually formed by a solution growth method, consistent film formation in a vacuum is difficult. Furthermore, when forming the absorption layer, it takes time to heat the substrate and stabilize it at about 500 ° C. Therefore, in practice, it is difficult to consistently form the back electrode layer, the absorption layer, the pn junction formation layer, and the surface electrode layer at a high speed.

  As described above, in the conventional manufacturing method of the CIS solar cell, a series of thin films from the back electrode layer to the front electrode layer are continuously formed at high speed, and an absorption layer having good crystallinity and a pn junction is obtained. It is the present condition that cannot be done. Accordingly, an object of the present invention is to provide a method for producing a photovoltaic device capable of consistently forming a surface electrode layer from a back electrode layer at a high speed.

  In the present invention, after a plurality of semiconductor precursor layers made of the elements constituting the absorption layer of the photovoltaic device and a layer other than the absorption layer of the photovoltaic device are formed in advance, the semiconductor precursor layer is heated, and the absorption layer By improving the crystallinity and simultaneously forming a pn junction, high-speed consistent film formation is possible.

Thus, according to the present invention, the following (1) to (20) are provided.
(1) A method for producing a photovoltaic device including a semiconductor layer that generates power by light irradiation, wherein a back electrode layer is formed on an insulating substrate, and the back electrode is formed. On the layer, a precursor layer forming step of forming a plurality of semiconductor precursor layers made of a crystal type element different from the crystal of the element constituting the semiconductor layer, and the formed semiconductor precursor The semiconductor precursor is formed after the surface electrode layer forming step for forming the surface electrode layer on the body layer, the back electrode layer forming step, the precursor layer forming step, and the surface electrode layer forming step. And a precursor layer diffusion step of heating the layer to produce a semiconductor crystal (Claim 1).

(2) The photovoltaic device manufacturing method according to claim 1, wherein in the precursor layer diffusion step, a plurality of the semiconductor precursor layers are diffused mutually by melt diffusion. A device manufacturing method (claim 2).
(3) The method for manufacturing a photovoltaic device according to claim 1 or 2, wherein in the precursor layer diffusion step, the semiconductor precursor layer is heated by irradiating the semiconductor precursor layer with electromagnetic waves. A method for producing a photovoltaic device, characterized in that (Claim 3).
(4) The method for producing a photovoltaic device according to claim 3, wherein, in the precursor layer diffusing step, the electromagnetic wave is an infrared ray (invention 4).
(5) The method for manufacturing a photovoltaic device according to claim 4, wherein, in the precursor layer diffusing step, the infrared light source is a halogen lamp (claim). 5).

(6) The method for producing a photovoltaic device according to any one of claims 1 to 5, wherein in the precursor layer diffusion step, a semiconductor precursor layer containing at least one layer of sulfur (S) is provided. A method for producing a photovoltaic device, characterized in that a film is formed (claim 6).
(7) The method for producing a photovoltaic device according to claim 6, wherein the semiconductor precursor layer containing the sulfur (S) is formed before and after the semiconductor precursor layer. A method for producing a photovoltaic device, characterized by having a melting point higher than the melting point of the layer (Claim 7).
(8) The photovoltaic device manufacturing method according to claim 6 or 7, wherein the semiconductor precursor layer containing sulfur (S) is formed by sputtering. (8).
(9) The method for manufacturing a photovoltaic device according to any one of claims 6 to 8, wherein the semiconductor precursor layer containing sulfur (S) is made of a sputtering gas containing hydrogen sulfide. A method of manufacturing a photovoltaic device, wherein the film is formed by sputtering.

(10) The method for manufacturing a photovoltaic device according to any one of claims 1 to 9, wherein the melting point of the crystal of the element constituting the semiconductor precursor layer is the amount of the element constituting the semiconductor layer. A method for producing a photovoltaic device, wherein the temperature is lower than the melting point of the crystal (claim 10).
(11) The method for manufacturing a photovoltaic device according to any one of claims 1 to 10, wherein the semiconductor layer is composed of a crystal of a chalcopyrite type compound. Manufacturing method (claim 11).
(12) The method for manufacturing a photovoltaic device according to any one of claims 1 to 11, wherein the semiconductor layer contains at least copper (Cu), indium (In), and selenium (Se). A method for manufacturing a photovoltaic device, characterized in that: (Claim 12).
(13) The photovoltaic device manufacturing method according to any one of claims 1 to 12, wherein the back electrode layer film forming step, the precursor layer film forming step, and the front electrode layer film forming step are performed. A method for manufacturing a photovoltaic device, wherein each step is performed in a vacuum and a vacuum state is maintained between the steps (Claim 13).
(14) The method for manufacturing a photovoltaic device according to any one of claims 1 to 13, wherein the back electrode layer forming step, the precursor layer forming step, and the front electrode layer forming step are performed. , Both of which are performed by sputtering, A method for manufacturing a photovoltaic device (claim 14).

(15) A method for producing a photovoltaic device comprising a semiconductor layer that generates power by light irradiation, a surface electrode layer forming step for forming a surface electrode layer on a glass substrate, and the formed surface electrode On the layer, a precursor layer forming step of sequentially forming an n-type semiconductor forming precursor layer, a diffusion control precursor layer, and a p-type semiconductor forming precursor layer, and the formed p-type A back electrode layer forming step of forming a back electrode layer on the semiconductor forming precursor layer; the n-type semiconductor forming precursor layer; the diffusion controlling precursor layer; and the p-type semiconductor forming precursor. And a precursor layer diffusion step of heating the layer and generating a semiconductor crystal by melt diffusion (Claim 15).

(16) comprising an insulating substrate, a surface electrode layer and a back electrode layer formed on the insulating substrate, and a chalcopyrite semiconductor layer disposed between the surface electrode layer and the back electrode layer, A photovoltaic device (Claim 16), wherein a cavity penetrating from the front electrode layer side to the back electrode layer side is formed in the chalcopyrite type semiconductor layer.
(17) The photovoltaic device according to claim 16, wherein the chalcopyrite semiconductor layer is a portion not in contact with an adjacent layer, and the adjacent layer is affected by the surface shape of the chalcopyrite semiconductor layer. A photovoltaic device, wherein a portion having a shape not received is formed (claim 17).

(18) A photovoltaic device including at least a front electrode layer, an absorption layer, and a back electrode layer in order from the light incident side, wherein copper (Cu), indium (In), and selenium (Se) are contained in the absorption layer. A photovoltaic device comprising: a sulfurized layer containing sulfur (S) contained inside the absorbing layer (claim 18).
(19) The photovoltaic device according to (18), wherein the sulfide layer contains CuInS ₂ crystal (claim 19).
(20) The photovoltaic device according to claim 18 or 19, wherein the sulfide layer has a composition ratio of copper (Cu) contained on the surface electrode layer side of the sulfide layer, the back surface of the sulfide layer. A photovoltaic device having a smaller Cu composition ratio on the electrode layer side (claim 20).

  In CIS solar cells, a semiconductor layer responsible for power generation is generally referred to as an absorption layer. However, since the photovoltaic element obtained by the photovoltaic element manufacturing method to which the present invention is applied can also be applied to solar cells other than CIS solar cells, the absorption layer will be referred to as a semiconductor layer in the following description. There is.

  According to the method for manufacturing a photovoltaic device according to claim 1, a series of thin films such as a back electrode, a semiconductor precursor layer, and a front electrode constituting the photovoltaic device are formed, and then heat treatment is performed. Without maintaining the temperature of the substrate at a high temperature in the film, the crystal of the semiconductor layer can be prepared to the desired crystal type and a pn junction can be formed at the same time, making it possible to manufacture photovoltaic devices by high-speed and consistent operation become.

  According to the method for manufacturing a photovoltaic device according to claim 2, by melting and diffusing the semiconductor precursor layer, a semiconductor layer with few lattice defects and good crystallinity can be obtained.

  According to the method for manufacturing a photovoltaic device according to claim 3, by irradiating the semiconductor precursor layer with electromagnetic waves, the semiconductor precursor layer can be heated to a temperature equal to or higher than the heat resistant temperature of the substrate. Further, a semiconductor layer having good crystallinity can be obtained.

  According to the method for manufacturing a photovoltaic device according to claims 4 and 5, the semiconductor precursor layer can be heated using a low-cost, high-output light source.

According to the method for manufacturing a photovoltaic device according to claim 6, by providing a semiconductor precursor layer containing sulfur (S) in the semiconductor layer, a part of the semiconductor precursor layer has a high melting point and a high density. Therefore, diffusion of elements such as Cu, In, and Se can be easily controlled. Furthermore, since the finally produced sulfide is a chalcopyrite type crystal, which is the same as CuInSe ₂ , adverse effects on power generation efficiency can be minimized.

  According to the method for manufacturing a photovoltaic device according to claim 7, the diffusion of elements such as Cu, In, and Se is controlled by controlling the composition of the sulfide layer to obtain a relatively high melting point. Is possible.

  According to the method for manufacturing a photovoltaic device according to the eighth aspect, the composition distribution and the in-plane distribution of the film thickness of each layer can be reduced, and the area can be easily increased.

  According to the method for manufacturing a photovoltaic device according to claim 9, since it is possible to form a sulfide film by reactive sputtering, it is easy to reduce the cost of the sputtering target, improve the sputtering rate, and add a small amount of sulfur. Therefore, the controllability is improved.

According to the method for manufacturing a photovoltaic device according to claim 10, the melting point of the crystal of the element constituting the semiconductor precursor layer is lower than the melting point of the element constituting the semiconductor layer, whereby the semiconductor precursor layer The heating temperature can be reduced or the heating time can be shortened, damage to the substrate is reduced, and problems such as film peeling due to volume expansion of the substrate are reduced.
Here, when the melting point of the crystal of the element constituting the semiconductor precursor layer is higher than the melting point of the element constituting the semiconductor layer, the crystal growth of the semiconductor layer is caused by the undiffused residual compound generated during the heat treatment. Tends to be disturbed.

According to the method for manufacturing a photovoltaic device according to claim 11 and claim 12, by adopting a chalcopyrite compound crystal as the semiconductor layer, the composition range of elements used in the semiconductor precursor layer is dramatically increased. The photovoltaic device obtained by enlarging can be applied to solar cells, light receiving devices, and the like that require similar characteristics. Furthermore, since the melting point of the material containing copper (Cu), indium (In), and selenium (Se) is lower than the melting point (986 ° C.) of CuInSe ₂ that is a chalcopyrite type compound in most composition regions, the semiconductor precursor The degree of freedom of body layer design is expanded.

  According to the method for manufacturing a photovoltaic device according to claim 13, each step is performed in a vacuum, and the vacuum state is maintained between the steps, so that surface oxidation of each layer can be prevented. Thus, a high-quality photovoltaic device can be obtained.

  According to the method for manufacturing a photovoltaic device according to claim 14, the composition distribution of elements constituting each layer and the in-plane distribution of the film thickness of each layer can be reduced by performing each step by sputtering. It is possible to easily increase the area.

  According to the method for manufacturing a photovoltaic device according to claim 15, the surface electrode layer, the n-type semiconductor formation precursor layer, the diffusion control precursor layer, the p-type semiconductor formation precursor layer, and the back surface are formed on the glass substrate. By producing a photovoltaic element by forming an electrode layer, a photovoltaic element that generates power by light irradiation from the glass substrate side can be obtained.

  According to the photovoltaic device of claim 16, the chalcopyrite semiconductor layer has a cavity penetrating from the surface electrode layer side to the back electrode layer side, so that the surface electrode layer, the back electrode layer, Can prevent short circuit.

  According to the photovoltaic device of claim 17, a portion of the chalcopyrite type semiconductor layer that is not in contact with the adjacent layer, and the adjacent layer is not affected by the surface shape of the chalcopyrite type semiconductor layer ( By forming the voids, the intrusion of the compound from the front electrode layer or the back electrode layer can be prevented, and a short circuit can be prevented.

  According to the photovoltaic device of claim 18, mutual diffusion between the n-type semiconductor layer and the p-type semiconductor layer can be suppressed, and the pn junction becomes a chemically stable sulfide. Therefore, the conversion efficiency is improved and the thermal stability is improved at the same time.

According to the photovoltaic device of claim 19, the CuInS ₂ crystal can reduce the width of the depletion layer formed between the n-type semiconductor layer and the p-type semiconductor layer, thereby improving the voltage. It becomes possible to make it.

  According to the photovoltaic device of claim 20, the composition band offset between the n-type semiconductor layer and the n-type semiconductor layer is improved on the surface electrode layer side of the sulfide layer by forming a composition gradient of Cu in the sulfide layer. In addition, since the conduction band offset between the sulfide layer and the p-type semiconductor layer is improved on the back electrode layer side, the conversion efficiency is improved.

  Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention. The drawings used are for explaining the present embodiment and do not represent the actual size.

  First, the outline of the manufacturing process in the present embodiment will be described. FIG. 1 is a diagram illustrating an outline of a manufacturing process in a method for manufacturing a photovoltaic device to which the present embodiment is applied. As shown in FIG. 1, in the photovoltaic device manufacturing method to which the present embodiment is applied, a predetermined sputtering apparatus is used, and a back electrode layer, a semiconductor precursor layer, and a surface electrode layer are formed on an insulating substrate by a sputtering method. A film is formed (multilayer thin film forming step). Here, the semiconductor precursor layer preferably contains selenium (Se).

Next, the insulating substrate on which the back electrode layer, the semiconductor precursor layer, and the front electrode layer are formed is applied to the compound constituting the semiconductor precursor layer using a predetermined heating device (for example, light irradiation with a halogen lamp). Heating above the melting point generates semiconductor crystals (annealing step). In this case, as a device to be used, only one predetermined sputtering device and one heating device may be used. Also, no toxic gas treatment facility or waste liquid treatment facility is required. Furthermore, since the number of processes is small, the cost can be significantly reduced.
Next, the photovoltaic element in this Embodiment is demonstrated.

(Embodiment 1)
FIG. 2 is a diagram for explaining the first embodiment of the photovoltaic element to which the present embodiment is applied. The same code | symbol is used about the structure similar to the photovoltaic device shown in FIG.
As shown in FIG. 2A, the photovoltaic element precursor _I0 is manufactured by first forming a back electrode layer 2 made of a metal material on a substrate 1 that is an insulating substrate. Next, a p-type semiconductor formation precursor layer 8a, a diffusion control precursor layer 8b, and an n-type semiconductor formation precursor layer 8c are sequentially formed on the back electrode layer 2 as a plurality of semiconductor precursor layers 8. Film (semiconductor precursor layer 8). Subsequently, a surface electrode layer 5 made of a transparent electrode material is formed thereon. Each layer is formed by sputtering using a predetermined sputtering apparatus.
Next, infrared rays 9 as electromagnetic waves are irradiated for a certain time from the surface electrode layer 5 side, and the p-type semiconductor forming precursor layer 8a, the diffusion control precursor layer 8b as the plurality of semiconductor precursor layers 8 described above, and The n-type semiconductor forming precursor layer 8c is heated. A halogen lamp is preferable as the light source of the infrared ray 9.

  The compounds contained in each of the p-type semiconductor formation precursor layer 8a, the diffusion control precursor layer 8b, and the n-type semiconductor formation precursor layer 8c irradiated with the infrared rays 9 diffuse to each other by melt diffusion. Then, as shown in FIG. 2B, the semiconductor layer 3 including the p-type semiconductor layer 3a and the n-type semiconductor layer 3b is formed, and the photovoltaic device I is manufactured. Thereafter, a comb-shaped electrode (negative electrode) for collecting current is provided on the surface electrode layer 5 by sputtering, and an electrode (positive electrode) is placed on the back electrode layer 2 by sputtering or printing a conductive paste (not shown). )

Here, when a Cu—In—Se based semiconductor containing copper (Cu), indium (In), and selenium (Se) is employed as the semiconductor layer 3, the p-type semiconductor forming precursor layer 8 a is p-type. It is preferable to form a film from a mixture of copper (Cu) and selenium (Se) that easily forms a semiconductor. Further, the n-type semiconductor forming precursor layer 8c is desirably a mixture of indium (In) and selenium (Se) that easily forms an n-type semiconductor.
The diffusion control precursor layer 8b is a layer for controlling mutual diffusion between the p-type semiconductor formation precursor layer 8a and the n-type semiconductor formation precursor layer 8c. The p-type semiconductor forming precursor layer 8a and the n-type semiconductor forming precursor are controlled by controlling the elemental composition, melting point and film thickness of the diffusion controlling precursor layer 8b of the compound constituting the diffusion controlling precursor layer 8b. It becomes possible to control the diffusion of the layer 8c with each other by melt diffusion.

In the method for manufacturing a photovoltaic device to which the present embodiment is applied, the element composition of the compound constituting the plurality of semiconductor precursor layers and the film thickness of each semiconductor precursor layer are changed to melt the semiconductor precursor layer By diffusion, a semiconductor layer having good crystallinity can be generated and a pn junction can be formed at the same time.
This will be described by taking as an example the case of adopting a CuInSe ₂ -based compound that is one of chalcopyrite type compounds as the compound constituting the semiconductor layer.

FIG. 3 is a diagram showing the relationship between the Se concentration and the melting point (° C.) of the Cu—Se compound. FIG. 4 is a graph showing the relationship between the Se concentration of the In—Se compound and the melting point (° C.).
In general, CuInSe ₂ can be obtained by reacting Cu ₂ Se and In ₂ Se ₃ which are stable compounds with 50 mol% each. Here, it is known that both Cu ₂ Se and In ₂ Se ₃ have a melting point higher than the melting point (986 ° C.) of CuInSe _{2 as} the final product in each binary phase diagram (for example, Cu ₂ Se has a melting point of 1,130 ° C.). Therefore, when diffusing the Cu 2 _Se and an In ₂ Se ₃ by heat treatment, it is possible that these compounds remains remain unreacted.
Therefore, instead of using Cu ₂ Se and In ₂ Se ₃ , CuSe and InSe, which are compounds having a lower melting point than these compounds, are each melted and diffused by 50 mol% to leave unreacted compounds. The possibility is likely to decrease.

However, when these low-melting-point compounds are heated, melt diffusion proceeds rapidly, and only the p-type CuInSe ₂ compound is generated, making it difficult to form a pn junction.
For this reason, it is possible to control interdiffusion of InSe and CuSe by disposing a compound having a higher melting point than these compounds between the InSe compound layer and the CuSe compound layer. As a result, a chalcopyrite n-type Cu—In—Se film slightly lacking Cu is formed on the negative electrode side, whereas a chalcopyrite p-type Cu slightly lacking In is formed on the positive electrode side. It is considered that an -In-Se film is formed.

Furthermore, as shown in FIG. 3, the relationship between the Se concentration and the melting point (° C.) of the Cu—Se compound is such that the Se concentration is in the range of 33.3 at% to 52.5 at%, and the melting point (° C.) rapidly increases. You can see that it changes. Further, as shown in FIG. 4, it can be seen that the relationship between the Se concentration of the In—Se compound and the melting point (° C.) changes rapidly when the Se concentration is in the range of 50 at% to 60 at%.
By utilizing such properties of the Cu—Se compound and the In—Se compound, the p-type semiconductor formation precursor layer 8a (see FIG. 2) and the n-type semiconductor formation precursor layer 8c (see FIG. 2). ) And the diffusion direction and amount of each compound can be controlled at the same time.

That is, the n-type semiconductor forming precursor layer 8c (see FIG. 2) is formed using an In—Se compound in which the melting point rises when the Se concentration is increased in the range of Se concentration from 50 at% to 60 at%. . In addition, the p-type semiconductor forming precursor layer 8a (see FIG. 2) is made of a Cu—Se compound that has a Se concentration in the range of 33.3 at% to 52.5 at% and whose melting point decreases as the Se concentration increases. To form a film. Then, the melting points of the p-type semiconductor forming precursor layer 8a and the n-type semiconductor forming precursor layer 8c are controlled by adjusting the concentration of Se contained in the diffusion control precursor layer 8b (see FIG. 2). At the same time, the direction and amount of diffusion can be controlled.
As a result, a pn junction is formed in the semiconductor layer 3 generated by melting and diffusion of the plurality of semiconductor precursor layers 8, and the width and depth distribution of the depletion layer near the formed pn junction can be controlled. Is possible.

(Embodiment 2)
FIG. 5 is a diagram for explaining a photovoltaic device according to a second embodiment to which the present embodiment is applied. The same components as those of the photovoltaic device I (Embodiment 1) shown in FIG. As shown in FIG. 5A, the photovoltaic element precursor II ₀ is manufactured by forming seven semiconductor precursor layers (semiconductor precursor layer 10) on the back electrode layer 2 formed on the substrate 1. Laminated.
Among these, the five semiconductor precursor layers on the back electrode layer 2 side are p-type semiconductor forming precursor layers 10a, 10b, 10c, 10d, and 10e, and the light shown in FIG. The overall composition and the film thickness of each layer are adjusted so that the p-type semiconductor layer 3a of the power generation element II is formed. Further, the one semiconductor precursor layer in contact with the surface electrode layer 5 is an n-type semiconductor forming precursor layer 10g, and the n-type semiconductor layer 3b of the photovoltaic device II shown in FIG. It is formed.

Further, one semiconductor precursor layer sandwiched between the p-type semiconductor forming precursor layer 10e and the n-type semiconductor forming precursor layer 10g is a diffusion control precursor layer 10f, and the diffusion control precursor layer. It functions as a diffusion control layer for controlling the mutual diffusion between the p-type semiconductor forming precursor layer 10e and the n-type semiconductor forming precursor layer 10g adjacent to 10f. Specifically, when the diffusion control precursor layer 10f is melted and diffused, the p-type semiconductor formation precursor layer 10e and the n-type semiconductor formation precursor layer 10g adjacent to the diffusion control precursor layer 10f are formed. The melting point of each interface is increased, and the diffusion of elements that generate the p-type semiconductor is suppressed from the p-type semiconductor forming precursor layer 10a to 10e side to the n-type semiconductor forming precursor layer 10g side.
In this way, by forming the semiconductor precursor layer as a multilayer of about seven layers, a pn junction is formed in the semiconductor layer 3 generated by the melting and diffusion of the multilayer semiconductor precursor layer, and a depletion layer near the pn junction is formed. It is possible to control the distribution in the width and depth directions of the lens more precisely.

(Embodiment 3)
FIG. 6 is a diagram for explaining a photovoltaic device according to a third embodiment to which the present embodiment is applied. The same components as those of the photovoltaic device I (Embodiment 1) shown in FIG. As shown in FIG. 6A, the photovoltaic element precursor III ₀ is manufactured by forming seven semiconductor precursor layers (semiconductor precursor layer 11) on the back electrode layer 2 formed on the substrate 1. Laminated.
Among these, the three semiconductor precursor layers on the back electrode layer 2 side are the p-type semiconductor forming precursor layers 11a, 11b, and 11c, and the photovoltaic element III shown in FIG. The overall composition and the film thickness of each layer are adjusted so that the p-type semiconductor layer 3a is formed. Further, the three semiconductor precursor layers in contact with the surface electrode layer 5 are n-type semiconductor forming precursor layers 11e, 11f, and 11g, and the n-type of the photovoltaic element III shown in FIG. Semiconductor layer 3b is formed.

Further, one semiconductor precursor layer sandwiched between the p-type semiconductor forming precursor layer 11c and the n-type semiconductor forming precursor layer 11e is a diffusion control precursor layer 11d, and is a diffusion control precursor. The p-type semiconductor forming precursor layer 11c adjacent to the layer 11d functions as a diffusion control layer for controlling mutual diffusion between the n-type semiconductor forming precursor layer 11e. Specifically, the melting point of the diffusion control precursor layer 11d is set to be higher than the melting point of the p-type semiconductor forming precursor layer 11c and the melting point of the n-type semiconductor forming precursor layer 11e.
By doing so, interdiffusion between the p-type semiconductor forming precursor layer 11c and the n-type semiconductor forming precursor layer 11e is suppressed, and as in the photovoltaic element III shown in FIG. It becomes possible to form the n-type semiconductor layer 3b on the type semiconductor forming precursor layer 11e side and the p-type semiconductor layer 3a on the p-type semiconductor forming precursor layer 11c side.

(Embodiment 4)
In the photovoltaic elements (I to III) shown in the above-described three types of embodiments (Embodiments 1 to 3), the back electrode layer 2 made of a metal material is formed on the substrate 1. For this reason, power generation by sunlight through the substrate 1 cannot be performed. For this reason, it is actually necessary to further provide tempered glass on the surface electrode layer 5 side through a resin film or the like. Therefore, the embodiment described below has a layer structure opposite to the above-described three types of embodiments.

FIG. 7 is a diagram for explaining a photovoltaic device according to a fourth embodiment to which the present embodiment is applied. The same components as those of the photovoltaic device I (Embodiment 1) shown in FIG.
As shown in FIG. 7 (a), the production of photovoltaic devices precursor IV ₀ is on the surface electrode layer 5 made of a transparent electrode material was formed on the substrate 1 made of tempered glass, a precursor for the n-type semiconductor formed The body layer 8c, the diffusion control precursor layer 8b, and the p-type semiconductor forming precursor layer 8a are sequentially formed, and the back electrode layer 2 made of a metal material is formed on the p-type semiconductor forming precursor layer 8a. . Each layer is formed by sputtering using a predetermined sputtering apparatus.

  Next, infrared rays 9 as electromagnetic waves are irradiated for a certain time from the surface electrode layer 5 side, and the p-type semiconductor formation precursor layer 8a, the diffusion control precursor layer 8b, and the n-type semiconductor formation precursor layer 8c are heated. To do. Then, by melting and diffusing these, as shown in FIG. 7B, the semiconductor layer 3 composed of the p-type semiconductor layer 3a and the n-type semiconductor layer 3b of the photovoltaic element IV is formed. In this case, the substrate 1 made of tempered glass also serves as the substrate 1 in the above-described three types of Embodiments 1 to 3, and is effective for cost reduction.

(Embodiment 5)
In the photovoltaic device precursor I ₀ (see FIG. 2) to the photovoltaic device precursor IV ₀ (see FIG. 7) described in the first to fourth embodiments, the diffusion control precursor layers 8b and 10f are used. , 11d, a layer containing sulfur (S) can be formed. Sulfur (S) is contained, for example, as a sulfide such as Cu ₂ S or In ₂ S ₃ .
Here, sulfur is a chalcogenide element like selenium and reacts with CuIn. Therefore, to form similarly chalcopyrite compounds and CuInSe _2. In general, sulfides have a higher melting point than chemically selenides and are chemically stable.
When the diffusion control precursor layer is formed using sulfide, it becomes easy to control element diffusion between the n-type semiconductor formation precursor layer and the p-type semiconductor formation precursor layer.

Here, the diffusion control precursor layer containing sulfur (S) preferably has a melting point higher than that of other semiconductor precursor layers formed before and after the diffusion control precursor layer.
Moreover, the precursor layer for diffusion control containing sulfur (S) is formed by sputtering. At this time, it is preferable to form a film by sputtering using a sputtering gas containing hydrogen sulfide.

(Other embodiments)
In the present embodiment, as shown in FIG. 2, the semiconductor precursor layer 8 is melted and diffused by irradiating infrared rays 9 from the surface electrode layer 5 side. However, the direction of irradiating the infrared rays 9 is not necessarily limited to the surface electrode layer 5 side. For example, if the substrate 9 is made of tempered glass that transmits infrared rays 9, the infrared rays 9 are emitted from the substrate 1 side. It is also possible to irradiate.

In this case, the infrared ray 9 is reflected on the back surface of the substrate 1, and the infrared ray 9 may be absorbed depending on the type of material used for the substrate 1. Furthermore, the energy loss of the infrared rays 9 may be caused by reflection at the metal back electrode layer 2. However, in this case, the metal back electrode layer 2 having a relatively high thermal conductivity generates heat, whereby the semiconductor precursor layer is heated, and there is a merit that uneven heating due to irradiation with infrared rays 9 is reduced.
Furthermore, even when there is a difference in internal stress, a difference in thermal expansion coefficient, or the like between any of the layers from the laminated back electrode layer 2 to the front electrode layer 5, film peeling due to infrared irradiation can be suppressed.
In addition, as an electromagnetic wave source used for heating the semiconductor precursor layer, various lasers, various lamps that generate light other than infrared rays, and radiant heat radiated from heating wires can be used.

In addition, the above description is only an example for demonstrating embodiment of this invention, and this invention is not limited to this embodiment.
The present invention can be applied to a photovoltaic device comprising a semiconductor layer composed of a plurality of elements and two electrode layers sandwiching the semiconductor layer, and a method for producing a photovoltaic device having such a structure. For example, a III-V group semiconductor typified by a Cd-Te system, an I-III-VI group semiconductor typified by a Cu-In-Se system, and an I-II typified by a Cu-Zn-Sn-S system compound The present invention can also be applied to an IV group semiconductor composed of two or more elements such as an -IV-VI group semiconductor, an II-IV-V group semiconductor, and a Si-Ge group.

  Furthermore, in the embodiment described above, no buffer layer is provided between the semiconductor layer 3 and the surface electrode layer 5, but the buffer layer 4 can be provided as necessary. By providing a buffer layer between the semiconductor layer 3 and the surface electrode layer 5, defects generated at the interface between the semiconductor layer 3 and the surface electrode layer 5 can be suppressed.

  Hereinafter, the present embodiment will be described in more detail based on examples. Note that the present embodiment is not limited to the following examples.

Example 1
FIG. 8 is a diagram illustrating a cross-sectional structure of the photovoltaic element precursor manufactured in Example 1. The photovoltaic element precursor V ₀ shown in FIG. 8 is formed on the Mo (molybdenum) layer 13 as the back electrode layer formed on the glass substrate 12, and the first In—Se layer 14 as the p-type semiconductor forming precursor layer. The first Cu—Se layer 15, the second In—Se layer 16, the second Cu—Se layer 17 as the diffusion control precursor layer, and the third In—Se layer 18 as the n-type semiconductor formation precursor layer are sequentially laminated. Further, an Al—Zn—O layer 19 was formed as a surface electrode layer. Table 1 shows the composition and film thickness of each layer.

Next, a 140 W halogen lamp is condensed in a range of about 1 cm in diameter, and from the surface electrode layer (Al—Zn—O layer 19) side of the photovoltaic element precursor V ₀ in which the above-described layers are laminated, The semiconductor precursor layer was irradiated with infrared rays 4 for 4 minutes to melt and diffuse the semiconductor precursor layer, thereby producing a photovoltaic device (not shown). After that, when an electrode for current collection was provided on the surface electrode layer (Al—Zn—O layer 19) side and irradiated with simulated sunlight, it was confirmed that power was generated.

(Example 2)
In order to confirm that the semiconductor layer of the photovoltaic device manufactured in Example 1 (in this case, chalcopyrite-type CuInSe _two layers) was obtained as a single layer, the semiconductor precursor layer shown in Table 1 and X-ray diffraction measurement was performed on the semiconductor layer formed by irradiating infrared rays 9. The results of X-ray diffraction measurement are shown in FIGS.

FIG. 9 is a result of X-ray diffraction measurement of each laminated film shown in Table 1 before infrared irradiation. FIG. 10 shows the X-ray diffraction measurement results of the semiconductor layer formed by irradiating each laminated film shown in Table 1 with infrared rays.
From the results shown in FIG. 9, a plurality of peaks that are considered to be crystal peaks such as CuSe, InSe, In ₂ Se _3, and a halo pattern indicating that the laminated semiconductor precursor layer contains an amorphous state, Was observed. However, a peak of 26.7 degrees (2θ) indicating the CuInSe ₂ crystal was not observed.
From the result shown in FIG. 10, after melting and diffusion by infrared irradiation, a sharp peak of 26.7 degrees (2θ) indicating that there is no heterogeneous phase such as In ₂ Se ₃ or CuSe and CuInSe ₂ crystal is observed. It can be seen that good crystals are obtained.

(Example 3)
In order to confirm that the semiconductor layer (chalcopyrite-type CuInSe _two layers) of the photovoltaic device manufactured in Example 1 was obtained as a single layer, the cross section of the semiconductor precursor layer portion before and after infrared irradiation was observed with an electron microscope. Went. The results of electron microscope observation are shown in FIGS.

  FIG. 11 is an electron micrograph showing a cross section of each laminated film shown in Table 1 before infrared irradiation. FIG. 12 is an electron micrograph of a cross section of the semiconductor layer portion formed by irradiating each laminated film shown in Table 1 with infrared rays. FIG. 13 is an electron micrograph obtained by photographing another cross section of the semiconductor layer portion formed by irradiating each laminated film shown in Table 1 with infrared rays.

  From the results shown in FIG. 11, each layer in which a plurality of semiconductor precursor layers were formed between the Mo layer 13 and the Al—Zn—O layer 19 (the first In—Se layer 14 and the first Cu layer) before the infrared irradiation. It can be seen that the -Se layer 15, the second In-Se layer 16, the second Cu-Se layer 17, and the third In-Se layer 18) retain the columnar structure formed during sputtering.

  From the results shown in FIG. 12, the semiconductor layer 3 in which the plurality of semiconductor precursor layers stacked between the Mo layer 13 and the Al—Zn—O layer 19 are melted and diffused after the infrared irradiation, and the columnar structure is not recognized. It can be seen that it is formed. Further, the semiconductor layer 3 is a part that is not in contact with the adjacent back electrode layer (Mo layer 13) or the front electrode layer (Al—Zn—O layer 19), and the adjacent layer is a chalcopyrite type. It can be seen that a portion (void K) having a shape not affected by the surface shape of the semiconductor layer is formed. From this, it was confirmed that melting and diffusion of a plurality of semiconductor precursor layers occurred by irradiation with infrared rays.

Furthermore, from the results shown in FIG. 13, the chalcopyrite semiconductor layer (semiconductor layer 3) has a cavity Q penetrating from the front electrode layer side (Al—Zn—O layer 19) to the back electrode layer side (Mo layer 13). It can be seen that is formed. In such a portion where the semiconductor layer 3 does not exist partially, the back electrode layer (Mo layer 13) and the front electrode layer (Al—Zn—O layer 19) are not in contact with each other, thereby preventing a short circuit in this portion. I understand that.
That is, when the semiconductor layer 3 is melted by using a conventional method, a missing portion of the semiconductor layer 3 due to a partially generated void K is generated, and the surface electrode layer (Al—Zn—O layer 19 is formed in the void K. ) And the back electrode layer (Mo layer 13) are short-circuited. On the other hand, if the manufacturing method of the present invention is used, void K is generated after the surface electrode layer (Al—Zn—O layer 19) and the back electrode layer (Mo layer 13) are formed in advance. A portion where the semiconductor layer 3 is missing due to K becomes a cavity Q, and a short circuit can be prevented.

As described above in detail, according to the method for manufacturing a photovoltaic device to which the present invention is applied, a plurality of semiconductor precursor layers composed of elements contained in the semiconductor layer of the photovoltaic device, and the semiconductor precursor layer Each layer other than the above is formed in advance and then heated to simultaneously form the crystal of the semiconductor layer and the pn junction, thereby enabling high-speed consistent film formation.
In addition, as described above, a photovoltaic device manufacturing method to which the present invention is applied is a photovoltaic device including a semiconductor layer composed of a plurality of elements and two electrode layers sandwiching the semiconductor layer. It can be applied to a manufacturing method.
The method for configuring the semiconductor precursor layer differs depending on the constituent element of each semiconductor layer, but basically, a semiconductor that is provided with at least three semiconductor precursor layers and is easy to form an n-type. A precursor layer is provided on the negative electrode side, a semiconductor precursor layer that is easy to form p-type is provided on the positive electrode side, and a diffusion control layer for controlling mutual diffusion of these layers may be provided between these layers. Very important.

It is a figure explaining the outline | summary of the manufacturing process in the manufacturing method of the photovoltaic device to which this Embodiment is applied. It is a figure explaining Embodiment 1 of the photovoltaic device to which this Embodiment is applied. It is a figure which shows the relationship between Se density | concentration of a Cu-Se type compound, and melting | fusing point (degreeC). It is a figure which shows the relationship between Se density | concentration of In-Se type compound, and melting | fusing point (degreeC). It is a figure explaining Embodiment 2 of the photovoltaic device to which this Embodiment is applied. It is a figure explaining Embodiment 3 of the photovoltaic device to which this Embodiment is applied. It is a figure explaining Embodiment 4 of the photovoltaic device to which this Embodiment is applied. 2 is a diagram illustrating a cross-sectional structure of a photovoltaic element precursor manufactured in Example 1. FIG. It is an X-ray-diffraction measurement result of each laminated film shown in Table 1 before infrared irradiation. It is an X-ray-diffraction measurement result of the semiconductor layer formed by irradiating each laminated film shown in Table 1 with infrared rays. It is the electron micrograph which image | photographed the cross section of the part of each laminated film shown in Table 1 before infrared irradiation. 2 is an electron micrograph of a cross section of a semiconductor layer portion formed by irradiating each laminated film shown in Table 1 with infrared rays. It is the electron micrograph which image | photographed the other cross section of the semiconductor layer part formed by irradiating each laminated film shown in Table 1 with infrared rays. It is a figure explaining the structure of a general CIS type solar cell. It is a figure explaining the manufacturing process of a general CIS type solar cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Back electrode layer, 3 ... Semiconductor layer, 3A ... Absorption layer, 3a ... P-type semiconductor layer, 3b ... N-type semiconductor layer, 4 ... Buffer layer, 5 ... Front electrode layer, 6 ... Positive electrode, 7 ... Comb electrodes, 8a, 10a, 10b, 10c, 10d, 10e, 11a, 11b, 11c ... Precursor layer for forming a p-type semiconductor, 8b, 10f, 11d ... Precursor layer for diffusion control, 8c, 10g, 11e 11f, 11g ... n-type semiconductor forming precursor layer, 9 ... infrared rays, 12 ... glass substrate, 13 ... Mo layer, 14 ... first In-Se layer, 15 ... first Cu-Se layer, 16 ... second In-Se. Layer, 17 ... second Cu-Se layer, 18 ... third In-Se layer, 19 ... Al-Zn-O layer

Claims (20)

A method for producing a photovoltaic device comprising a semiconductor layer that generates power by light irradiation,
A back electrode layer forming step of forming a back electrode layer on an insulating substrate;
A precursor layer film forming step of forming a plurality of semiconductor precursor layers formed of a crystal type element different from a crystal of an element forming the semiconductor layer on the formed back electrode layer;
A surface electrode layer forming step of forming a surface electrode layer on the semiconductor precursor layer formed;
A precursor layer diffusion step of heating the semiconductor precursor layer and generating semiconductor crystals after the backside electrode layer forming step, the precursor layer forming step, and the surface electrode layer forming step; A method for producing a photovoltaic device, comprising:   The method for manufacturing a photovoltaic device according to claim 1, wherein in the precursor layer diffusion step, the plurality of semiconductor precursor layers are diffused to each other by melt diffusion. In the precursor layer diffusion step, by irradiating the semiconductor precursor layer with electromagnetic waves,
The method for manufacturing a photovoltaic device according to claim 1, wherein the semiconductor precursor layer is heated.   The said electromagnetic wave is infrared rays in the said precursor layer spreading | diffusion process, The manufacturing method of the photovoltaic device of Claim 3 characterized by the above-mentioned.   5. The method for manufacturing a photovoltaic device according to claim 4, wherein, in the precursor layer diffusion step, the infrared light source is a halogen lamp.   6. The photovoltaic device manufacturing method according to claim 1, wherein in the precursor layer diffusion step, a semiconductor precursor layer containing at least one layer of sulfur (S) is formed. Method.   The said semiconductor precursor layer containing the said sulfur (S) has melting | fusing point higher than melting | fusing point of the other semiconductor precursor layer formed into a film before and behind the said semiconductor precursor layer, It is characterized by the above-mentioned. Manufacturing method of the photovoltaic device.   The said semiconductor precursor layer containing the said sulfur (S) is formed into a film by sputtering, The manufacturing method of the photovoltaic device of Claim 6 or 7 characterized by the above-mentioned.   9. The light according to claim 6, wherein the semiconductor precursor layer containing sulfur (S) is formed by sputtering using a sputtering gas containing hydrogen sulfide. A method for producing a power generation element.   10. The melting point of the crystal of the element constituting the semiconductor precursor layer is lower than the melting point of the crystal of the element constituting the semiconductor layer. Photovoltaic element manufacturing method.   The method for manufacturing a photovoltaic device according to any one of claims 1 to 10, wherein the semiconductor layer is made of a crystal of a chalcopyrite type compound.   The method for manufacturing a photovoltaic device according to claim 1, wherein the semiconductor layer contains at least copper (Cu), indium (In), and selenium (Se). .   Each process of the said back surface electrode layer film forming process, the said precursor layer film forming process, and the said surface electrode layer film forming process is performed in a vacuum, and a vacuum state is hold | maintained between each process, It is characterized by the above-mentioned. The manufacturing method of the photovoltaic device of any one of Claims 1 thru | or 12.   The light according to any one of claims 1 to 13, wherein the back electrode layer forming step, the precursor layer forming step, and the front electrode layer forming step are all performed by sputtering. A method for producing a power generation element. A method for producing a photovoltaic device comprising a semiconductor layer that generates power by light irradiation,
A surface electrode layer forming step of forming a surface electrode layer on a glass substrate;
A precursor layer forming step of sequentially forming an n-type semiconductor forming precursor layer, a diffusion control precursor layer, and a p-type semiconductor forming precursor layer on the surface electrode layer formed; ,
A back electrode layer forming step of forming a back electrode layer on the p-type semiconductor forming precursor layer formed;
A precursor layer diffusion step of heating the n-type semiconductor formation precursor layer, the diffusion control precursor layer and the p-type semiconductor formation precursor layer, and generating a semiconductor crystal by melt diffusion; A method for producing a photovoltaic device, comprising: An insulating substrate;
A front electrode layer and a back electrode layer formed on the insulating substrate;
A chalcopyrite type semiconductor layer disposed between the front electrode layer and the back electrode layer;
With
A photovoltaic device, wherein a cavity penetrating from the front electrode layer side to the back electrode layer side is formed in the chalcopyrite semiconductor layer.   The chalcopyrite type semiconductor layer is formed with a portion that is not in contact with the adjacent layer, and the adjacent layer is not affected by the surface shape of the chalcopyrite type semiconductor layer. The photovoltaic device according to claim 16. A photovoltaic device comprising at least a front electrode layer, an absorption layer, and a back electrode layer in order from the light incident side,
The light comprising copper (Cu), indium (In), and selenium (Se) in the absorption layer, and a sulfide layer containing sulfur (S) inside the absorption layer. Power generation element. The photovoltaic device according to claim 18, wherein the sulfide layer contains a CuInS ₂ crystal.   19. The sulfide layer, wherein a composition ratio of copper (Cu) contained on the surface electrode layer side of the sulfide layer is smaller than a Cu composition ratio of the sulfide layer on the back electrode layer side. 19. The photovoltaic device according to 19.

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