JP2005101240A - Photosensor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensor maximally utilizing an incident light and its manufacturing method for the photosensor. <P>SOLUTION: An i-type amorphous silicon film 2 and an antireflection film 3 composed of an amorphous silicon nitride or the like are formed successively on the main surface of an n-type single-crystal silicon substrate 1. A positive electrode 100 and a negative electrode 200 are mounted adjacently on the rear of the n-type silicon substrate 1. The positive electrode 100 has the i-type amorphous silicon film 5, a p-type amorphous silicon film 7, a rear electrode 9, and a collecting electrode 11 successively formed on the rear of the n-type silicon substrate 1. The negative electrode 200 has the i-type amorphous silicon film 4, an n-type amorphous silicon film 6, the rear electrode 8, and the collecting electrode 10 successively formed on the rear of the n-type silicon substrate 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photovoltaic device using a semiconductor junction and a method for manufacturing the photovoltaic device.

  In recent years, photovoltaic devices having a junction between an n-type single crystal silicon substrate and a p-type amorphous silicon film have been developed. In such a photovoltaic device, in order to improve the photoelectric conversion efficiency, the fill factor F.V. is maintained while maintaining a high short circuit current Isc and an open circuit voltage Voc. F. It is necessary to improve.

  However, since there are many interface states at the junction between the n-type single crystal silicon substrate and the p-type amorphous silicon film, carrier recombination occurs and the open circuit voltage Voc decreases.

  Therefore, in order to suppress carrier recombination at the junction between the n-type single crystal silicon substrate and the p-type amorphous silicon film, a substantial gap is formed between the n-type single crystal silicon substrate and the p-type amorphous silicon film. A photovoltaic device having a HIT (Heterojunction with Intrinsic Thin-Layer) structure in which an intrinsic amorphous silicon film (i-type amorphous silicon film) is inserted is proposed ( For example, see Patent Document 1).

This photovoltaic element receives light from the main surface side of the n-type single crystal silicon substrate and generates power in the n-type single crystal silicon substrate. The electric power generated at this time can be taken out by the electrodes provided on the main surface side and the back surface side.
JP-A-11-224954

  However, in the above photovoltaic element, the number of photons incident on the n-type single crystal silicon substrate is reduced due to light absorption by the electrode on the main surface side and the p-type amorphous silicon film, thereby limiting the power generation efficiency. .

  An object of the present invention is to provide a photovoltaic device that can make the best use of incident light and a method for manufacturing the photovoltaic device.

  In this specification, a crystalline semiconductor includes a single crystal semiconductor and a polycrystalline semiconductor, and an amorphous semiconductor includes an amorphous semiconductor and a microcrystalline semiconductor.

  An intrinsic amorphous semiconductor film is an amorphous semiconductor film that is not intentionally doped with impurities, and contains impurities inherently contained in semiconductor raw materials or impurities that are naturally mixed in the manufacturing process. An amorphous semiconductor film is also included.

  A photovoltaic device according to the present invention includes a crystalline semiconductor having one surface and another surface, and an intrinsic first amorphous semiconductor film and a one conductivity type in a first region on one surface of the crystalline semiconductor. A second amorphous semiconductor film containing an impurity indicating impurity and a first electrode in order, and the second region on one surface of the crystalline semiconductor includes an impurity having another conductivity type different from the one conductivity type A semiconductor layer and a second electrode are sequentially provided.

  In the photovoltaic device according to the present invention, when the crystalline semiconductor receives light from the other surface side, holes and electrons are generated, and the generated holes are the first amorphous semiconductor film and the second amorphous semiconductor film. The path through the semiconductor film and the first electrode and the path through the semiconductor layer and the second electrode are taken out through one of the paths, and the generated electrons are paths opposite to the holes. It is taken out through.

  In this case, since the first electrode and the second electrode are formed on one surface side, incident light does not deteriorate. Accordingly, incident light can be utilized to the maximum by receiving light from the other surface of the crystalline semiconductor.

  The crystalline semiconductor may include an impurity having one conductivity type. In this case, a pn junction is formed between the crystalline semiconductor and the semiconductor layer, and carriers are efficiently extracted.

  The semiconductor layer is a third amorphous semiconductor film containing an impurity having another conductivity type, and an intrinsic fourth amorphous system is provided between the crystalline semiconductor and the third amorphous semiconductor film. A semiconductor film may be further provided. In this case, carrier recombination between the crystalline semiconductor and the third amorphous semiconductor film is prevented, and power generation efficiency is improved.

  A common amorphous semiconductor film in which the first amorphous semiconductor film in the first region of the crystalline semiconductor and the fourth amorphous semiconductor film in the second region are continuous may be used. . In this case, one surface side of the crystalline semiconductor is covered with an intrinsic amorphous semiconductor film. This eliminates the exposed portion on the one surface side of the crystalline semiconductor, prevents recombination of carriers on the one surface side of the crystalline semiconductor, and improves power generation efficiency.

  The first region and the second region may be provided at an interval, and a protective layer may be provided on the surface of the crystalline semiconductor between the first region and the second region. In this case, the exposed portion at the interval between the first region and the second region is covered with the protective layer on the one surface side of the crystalline semiconductor. This eliminates the exposed portion on the one surface side of the crystalline semiconductor, prevents recombination of carriers on the one surface side of the crystalline semiconductor, and improves power generation efficiency.

  The semiconductor layer may be a doped layer in which the second region of the crystalline semiconductor is doped with an impurity having another conductivity type. In this case, electrical contact between the crystalline semiconductor and the second amorphous semiconductor is obtained by the doped layer.

  The substantially entire other surface may be a light incident surface. In this case, since the light is sufficiently incident from the other surface, the incident light can be utilized to the maximum extent.

  The method for manufacturing a photovoltaic device according to the present invention includes a step of forming an intrinsic first amorphous semiconductor film in a first region on one surface of a crystalline semiconductor, and a first amorphous semiconductor film A step of forming a second amorphous semiconductor film containing an impurity of one conductivity type thereon, and a semiconductor containing an impurity of another conductivity type different from the one conductivity type in a second region of one surface of the crystalline semiconductor A step of forming a layer, a step of forming a first electrode on the second amorphous semiconductor film, and a step of forming a second electrode on the semiconductor layer.

  In the method for manufacturing a photovoltaic device according to the present invention, the first amorphous semiconductor film, the second amorphous semiconductor film, and the first electrode are formed in the first region of one surface of the crystalline semiconductor. The semiconductor layer and the second electrode are formed in the second region of the one surface of the crystalline semiconductor.

  In this case, when the crystalline semiconductor receives light from the other surface side, holes and electrons are generated, and the generated holes are generated by the first amorphous semiconductor film, the second amorphous meter semiconductor film, and the first amorphous semiconductor film. The electron is taken out through one of the path through the electrode and the path through the semiconductor layer and the second electrode, and the generated electrons are taken out through the path opposite to the hole. . In this case, since the first electrode and the second electrode are provided on the one surface side of the crystalline semiconductor, reflection loss and absorption loss of light incident from the other surface side of the crystalline semiconductor can be suppressed. Therefore, incident light can be utilized to the maximum by receiving light from the other surface of the crystalline semiconductor.

  According to the photovoltaic device of the present invention, incident light can be utilized to the maximum by receiving light from the other surface of the crystalline semiconductor.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described.

  Fig.1 (a) is a top view which shows the back surface of the photovoltaic element 500 based on this Embodiment, FIG.1 (b) is a partially expanded view of Fig.1 (a).

  As shown in FIG. 1A, the photovoltaic element 500 has a rectangular shape. For example, the length of the short side is 5 cm and the length of the long side is 10 cm. The back surface of the photovoltaic element 500 includes a comb-shaped positive electrode 100 and a comb-shaped negative electrode 200. The positive electrode 100 and the negative electrode 200 extend in the short side direction of the photovoltaic element 500 and are alternately arranged. Electrodes 300 and 400 are provided along both long sides of the back surface of the photovoltaic element 500.

  As shown in FIG. 1B, collector electrodes 11 and 10 are provided on the positive electrode 100 and the negative electrode 200, respectively. The collector electrode 10 is connected to the electrode 300, and the collector electrode 11 is connected to the electrode 400.

  FIG. 2 is a schematic cross-sectional view showing the structure of the photovoltaic device 500 according to the present embodiment.

  As shown in FIG. 2, a reflection made of an i-type amorphous silicon film 2 (non-doped amorphous silicon film), amorphous silicon nitride or the like on the main surface (front surface) of an n-type single crystal silicon substrate 1. The prevention film 3 is formed in order. The main surface side of the n-type single crystal silicon substrate 1 is a light incident surface. A positive electrode 100 and a negative electrode 200 are provided adjacent to the back surface of the n-type single crystal silicon substrate 1.

  The positive electrode 100 includes a side i-type amorphous silicon film 5, a p-type amorphous silicon film 7, a back electrode 9, and a collector electrode 11 that are sequentially formed on the back surface of the n-type single crystal silicon substrate 1. The negative electrode 200 includes an i-type amorphous silicon film 4, an n-type amorphous silicon film 6, a back electrode 8, and a collector electrode 10 that are sequentially formed on the back surface of the n-type single crystal silicon substrate 1. In the photovoltaic element 500 of FIG. 2, the n-type single crystal silicon substrate 1 is a main power generation layer.

The back electrodes 8 and 9 are transparent electrodes made of ITO (indium tin oxide), SnO ₂ (tin oxide), ZnO (zinc oxide), or the like. The collector electrodes 10 and 11 are made of Ag (silver) or the like.

  The film thickness of the i-type amorphous silicon film 2 is, for example, about 10 nm, the film thickness of the antireflection film 3 is, for example, about 70 nm, and the film thickness of the i-type amorphous silicon films 4, 5 is, for example, about 15 nm. The thickness of the n-type amorphous silicon film 6 is, for example, about 20 nm, the thickness of the p-type amorphous silicon film 7 is, for example, about 10 nm, and the thickness of the back electrodes 8, 9 is, for example, about 70 nm. The film thickness of the collector electrodes 10 and 11 is, for example, about 200 nm, but is not limited thereto.

  Note that since the power generation efficiency is increased by shortening the carrier travel distance between the n-type single crystal silicon substrate 1 and the p-type amorphous silicon film 7, the width of the p-type amorphous silicon film 7 is n. A width wider than the width of the type amorphous silicon film 6 is preferable.

  The positive electrode 100 of the photovoltaic device 500 of the present embodiment has an i-type amorphous silicon film 5 between the n-type single crystal silicon substrate 1 and the p-type amorphous silicon film 7 in order to improve the pn junction characteristics. The negative electrode 200 is provided with an i-type amorphous silicon film 4 and an n-type amorphous silicon film 6 on the back surface of the n-type single crystal silicon substrate 1 in order to prevent carrier recombination. BSF (Back Surface Field) structure.

Next, a method for manufacturing the photovoltaic element 500 of FIG. 2 will be described. First, the cleaned n-type single crystal silicon substrate 1 is heated in a vacuum chamber. Thereby, moisture adhering to the surface of n-type single crystal silicon substrate 1 is removed. Thereafter, H ₂ (hydrogen) gas is introduced into the vacuum chamber, and the surface of the n-type single crystal silicon substrate 1 is cleaned by plasma discharge.

Next, SiH ₄ (silane) gas and H ₂ gas are introduced into the vacuum chamber, and the i-type amorphous silicon film 2 is formed on the main surface of the n-type single crystal silicon substrate 1 by plasma CVD (chemical vapor deposition). Form. Subsequently, SiH ₄ gas and NH ₃ (ammonia) gas are introduced into the vacuum chamber, and the antireflection film 3 is formed on the i-type amorphous silicon film 2 by plasma CVD.

Next, a metal mask is put on a part of the back surface of the n-type single crystal silicon substrate 1. Subsequently, SiH ₄ gas and H ₂ gas are introduced into the vacuum chamber, and the i-type amorphous silicon film 5 is formed on the back surface of the n-type single crystal silicon substrate 1 except for the metal mask by plasma CVD. . Subsequently, SiH ₄ gas, H ₂ gas and B ₂ H ₆ gas are introduced into the vacuum chamber to form a p-type amorphous silicon film 7 on the i-type amorphous silicon film 5 by plasma CVD. .

Next, a metal mask is placed on a part of the back surface of the n-type single crystal silicon substrate 1 so as to cover the i-type amorphous silicon film 5 and the p-type amorphous silicon film 7. Subsequently, SiH ₄ gas and H ₂ gas are introduced into the vacuum chamber, and the i-type amorphous silicon film 4 is formed on the back surface of the n-type single crystal silicon substrate 1 except for the metal mask by plasma CVD. . Subsequently, SiH ₄ gas, H ₂ gas and PH ₃ (phosphine) gas are introduced into the vacuum chamber to form an n-type amorphous silicon film 6 on the i-type amorphous silicon film 4 by plasma CVD. To do.

  Next, back electrodes 8 and 9 are formed on the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7 by sputtering, respectively. Further, collector electrodes 10 and 11 are formed on the back electrodes 8 and 9, respectively, by screen printing.

  In the photovoltaic device 500 of the present embodiment, the conductive silicon film, the transparent electrode, and the collector electrode on the light incident surface that hinder the effective use of incident light are not necessary. Thereby, the manufacturing process is shortened, the cost is reduced, and the incident light can be utilized to the maximum, so that the output voltage and the fill factor can be maximized.

  Further, although silicon nitride is used for the antireflection film 3 of the present embodiment, silicon oxide may be used. Furthermore, in the photovoltaic element 500 of the present embodiment, since it is not necessary to consider the interface characteristics of the main surface, the antireflection film 3 should be a material that has excellent light transmission and can prevent reflection of incident light. That's fine. Here, the refractive index of silicon is about 3.4, and the refractive index of a sealing material such as EVA (ethylene-vinyl acetate resin) that covers the photovoltaic element 500 when the photovoltaic element 500 is used is about Since it is 1.5, if it has a refractive index of 1.5-3.4, it can be used as the antireflection film 3. For example, the material shown in Table 1 is mentioned.

  Further, although the n-type amorphous silicon film 6 of the present embodiment is doped with P (phosphorus) as an impurity, it is not limited thereto. For example, a V group element such as As (arsenic) may be doped as an impurity. The p-type amorphous silicon film 7 is doped with B (boron) as an impurity, but is not limited thereto. For example, a group III element such as Al (aluminum) or Ga (gallium) may be doped as an impurity. Further, an n-type polycrystalline silicon substrate may be used instead of the n-type single crystal silicon substrate 1. Further, the i-type amorphous silicon films 2, 4, 5, the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7 may contain microcrystalline silicon.

  Further, instead of the n-type single crystal silicon substrate 1, the i-type amorphous silicon films 2, 4, 5, the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7 of the present embodiment, for example Other group IV elements such as SiC (silicon carbide), SiGe (silicon germanium), Ge (germanium), etc. may be used.

  Moreover, in the photovoltaic element 500 of this Embodiment, although the n-type single crystal silicon substrate 1 is used, it is not restricted to it. For example, an i-type amorphous silicon film and a silicon nitride film are formed on the main surface of a p-type single crystal silicon substrate, and a positive electrode 100 and a negative electrode 200 similar to those of the photovoltaic element 500 according to the present embodiment are provided on the back surface. May be.

  Furthermore, the present invention is not limited to the structure of the photovoltaic element 500 shown in FIG. 2, and can be applied to photovoltaic elements having other various structures. For example, the i-type amorphous silicon film 4 and the n-type amorphous silicon film 6 on the back surface of the n-type single crystal silicon substrate 1 may not be provided.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described.

  FIG. 3 is a schematic cross-sectional view showing the structure of the photovoltaic element 500a according to the second embodiment. The photovoltaic element 500a in FIG. 3 is different from the photovoltaic element 500 in FIG. 1 in that an n-type single crystal silicon substrate 1 is used instead of the i-type amorphous silicon film 4 and the n-type amorphous silicon film 6. The point is that the impurity diffusion layer 1a is provided therein.

  Impurity diffusion layer 1a is formed by thermally diffusing high-concentration P (phosphorus) in part of a region where i-type amorphous silicon film 5 is not formed on the back surface of n-type single crystal silicon substrate 1. Thereafter, the back electrode 8 and the collector electrode 10 are formed on the impurity diffusion layer 1a.

  In the present embodiment, since it is not necessary to form the i-type amorphous silicon film 4 and the n-type amorphous silicon film 6 when the negative electrode 200 is manufactured, the manufacturing process can be shortened.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described.

  FIG. 4 is a schematic cross-sectional view showing the structure of the photovoltaic element 500b according to the third embodiment. The photovoltaic element 500b in FIG. 4 is different from the photovoltaic element 500 in FIG. 1 in that the i-type amorphous silicon film 4 is in contact with the end of the p-type amorphous silicon film 7.

  Hereinafter, a method for manufacturing the photovoltaic element 500b of FIG. 4 will be described. The formation method of the i-type amorphous silicon film 2, the antireflection film 3, the i-type amorphous silicon film 5 and the p-type amorphous silicon film 7 on the main surface side of the n-type single crystal silicon substrate 1 is as follows. This is the same as the photovoltaic element 500 of FIG.

  When the i-type amorphous silicon film 4 and the n-type amorphous silicon film 6 are formed, the metal mask is aligned with the end faces of the i-type amorphous silicon film 5 and the p-type amorphous silicon film 7. Cover. Thereby, the entire back surface of the n-type single crystal silicon substrate 1 is covered with the i-type amorphous silicon films 4 and 5. As a result, carrier recombination in the exposed portion of n-type single crystal silicon substrate 1 is prevented, and power generation efficiency is improved.

(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described.

  FIG. 5 is a schematic cross-sectional view showing the structure of a photovoltaic element 500c according to the fourth embodiment. The photovoltaic element 500c in FIG. 5 differs from the photovoltaic element 500 in FIG. 1 in that an i-type amorphous silicon film 4 is formed on the entire back surface of the n-type single crystal silicon substrate 1. Thereby, recombination of carriers in the exposed portion of n-type single crystal silicon substrate 1 is prevented, and power generation efficiency is improved.

  Hereinafter, a method for manufacturing the photovoltaic element 500c of FIG. 5 will be described. The formation method of the i-type amorphous silicon film 2 and the antireflection film 3 on the main surface side of the n-type single crystal silicon substrate 1 is the same as that of the photovoltaic element 500 of FIG.

  After the i-type amorphous silicon film 4 is formed on the entire back surface of the n-type single crystal silicon substrate 1, an n-type amorphous silicon film 6 and a p-type amorphous silicon film 7 are formed. Thereby, it is not necessary to form the i-type amorphous silicon film 5, and the manufacturing process can be shortened.

(Fifth embodiment)
The fifth embodiment of the present invention will be described below.

  FIG. 6 is a schematic cross-sectional view showing the structure of a photovoltaic device 500d according to the fifth embodiment. The photovoltaic element 500d in FIG. 6 is different from the photovoltaic element 500c in FIG. 5 in that an impurity diffusion layer 4a is formed in the i-type amorphous silicon film 4 and the n-type amorphous silicon film 6 is i. It is a point formed on the entire surface of the type amorphous silicon film 4.

  Hereinafter, a method for manufacturing the photovoltaic element 500d of FIG. 6 will be described. The formation method of the i-type amorphous silicon film 2 and the antireflection film 3 on the main surface side of the n-type single crystal silicon substrate 1 is the same as that of the photovoltaic element 500 of FIG.

  A metal mask is put on a part of the region on the i-type amorphous silicon film 4. Subsequently, a high concentration group III element such as B is doped into the i-type amorphous silicon film 4 by a plasma doping method to form an impurity diffusion layer 4a. Thereafter, an n-type amorphous silicon film 6 is formed on the entire surface of the i-type amorphous silicon film 4.

  In the present embodiment, since the process of covering the metal mask when forming the n-type amorphous silicon film 6 is reduced, the manufacturing process can be shortened. Since the thickness of the n-type amorphous silicon film 6 is very small, the pn junction between the impurity diffusion layer 4a and the n-type amorphous silicon film 6 hardly affects the power generation efficiency.

(Sixth embodiment)
The sixth embodiment of the present invention will be described below.

FIG. 7 is a schematic cross-sectional view showing the structure of a photovoltaic device 500e according to the sixth embodiment. The photovoltaic element 500e in FIG. 7 is different from the photovoltaic element 500 in FIG.
The back electrode 9 is formed on the entire surface of the p-type amorphous silicon film 7, and the back electrode 8 is formed on the entire surface of the n-type amorphous silicon film 6.

  Hereinafter, a method for manufacturing the photovoltaic element 500c of FIG. 7 will be described. The formation method of the i-type amorphous silicon film 2 and the antireflection film 3 on the main surface side of the n-type single crystal silicon substrate 1 is the same as that of the photovoltaic element 500 of FIG.

  A back electrode 9 is formed using a metal mask used when the p-type amorphous silicon film 7 is formed, and a back electrode 8 is formed using a metal mask used when the n-type amorphous silicon film 6 is formed. To do. Thereby, the back electrode 9 can be formed on the entire surface of the p-type amorphous silicon film 7, and the back electrode 8 can be formed on the entire surface of the n-type amorphous silicon film 6. In this case, the number of times of positioning the metal mask is reduced, which is efficient.

  Further, before the i-type amorphous silicon films 4 and 5 are formed by the CVD method, a lift-off layer made of a linear resin is formed between the i-type amorphous silicon film 4 and the i-type amorphous silicon film 5. May be formed in advance by a screen printing method.

  In this case, the i-type amorphous silicon films 4 and 5, the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7 are formed by the method of FIG. A back electrode is formed on the entire surface of the type amorphous silicon film 7 and the lift-off layer, and the lift-off layer is removed. Thereby, the back surface electrodes 8 and 9 can be formed.

  Further, after forming the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7 of the photovoltaic element 500 of FIG. The back electrodes 8 and 9 may be formed by forming the silicon film 7 and the exposed portion of the n-type single crystal silicon substrate 1 and removing unnecessary regions of the back electrode by laser scribing. A partial region of the back electrode can be selectively removed by adjusting the laser irradiation conditions.

  In this case, excimer or YAG (yttrium aluminum garnet) SHG (second harmonic generation), THG (third harmonic generation), or the like can be used as the type of laser.

  Further, an unnecessary region of the back electrode may be removed using a mechanical scribe method instead of the laser scribe method.

  In the photovoltaic device 500e according to the present embodiment, the back electrodes 8 and 9 are formed on the entire surface of the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7, and therefore the n-type. Carriers can be efficiently collected from the amorphous silicon film 6 and the p-type amorphous silicon film 7. Thereby, the power generation efficiency of the photovoltaic element 500e is improved.

(Seventh embodiment)
The seventh embodiment of the present invention will be described below.

  FIG. 8 is a schematic cross-sectional view showing the structure of a photovoltaic element 500f according to the seventh embodiment. The photovoltaic element 500f in FIG. 8 differs from the photovoltaic element 500e in FIG. 7 in that the protective layer 12 made of a resin or the like is provided between the i-type amorphous silicon film 5 and the i-type amorphous silicon film 4. Is formed.

  By forming the protective layer 10 in advance by the screen printing method before forming the i-type amorphous silicon films 4 and 5, no back electrode is required by the laser scribe method, the mechanical scribe method, or the like described in FIG. When the region is removed, damage to the n-type single crystal silicon substrate 1 can be prevented.

(Eighth embodiment)
The eighth embodiment of the present invention will be described below.

  FIG. 9 is a schematic cross-sectional view showing the structure of a photovoltaic device 500g according to the eighth embodiment. The photovoltaic element 500g in FIG. 9 is different from the photovoltaic element 500e in FIG. 7 in that the i-type amorphous silicon film 4 is formed on the entire back surface of the n-type single crystal silicon substrate 1.

  After forming up to the i-type amorphous silicon film 4 by the method described in FIG. 5, the n-type amorphous silicon film 6, the p-type amorphous silicon film 7, and the back electrodes 9, 10 are formed by the method described in FIG. Further, by forming the collector electrodes 10 and 11, the photovoltaic element 500g of FIG. 9 can be manufactured.

  In the photovoltaic device 500g according to the present embodiment, since the i-type amorphous silicon film 4 is formed on the entire back surface of the n-type single crystal silicon substrate 1, the n-type single crystal silicon substrate 1 is exposed. Since the recombination of carriers in the portion is prevented and the back electrodes 8 and 9 are formed on the entire surface of the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7, the n-type amorphous Carriers can be efficiently collected from the silicon film 6 and the p-type amorphous silicon film 7. Thereby, the power generation efficiency is further improved.

(Ninth embodiment)
The ninth embodiment of the present invention will be described below.

  FIG. 10 is a schematic cross-sectional view showing the structure of a photovoltaic device 500h according to the ninth embodiment. The photovoltaic element 500h in FIG. 10 differs from the photovoltaic element 500e in FIG. 7 in that the i-type amorphous silicon film 4 is formed on the entire back surface of the n-type single crystal silicon substrate 1 and the n-type non-crystalline silicon film 4 is formed. A protective layer 12 made of a resin or the like is formed between the crystalline silicon film 6 and the p-type amorphous silicon film 7.

  Before forming the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7, the protective layer 10 is formed in advance by a screen printing method, whereby the laser scribe method and the mechanical scribe method described in FIG. For example, damage to the i-type amorphous silicon film 4 can be prevented when an unnecessary region of the back electrode is removed.

  In the photovoltaic device 500h according to the present embodiment, since the i-type amorphous silicon film 4 is formed on the entire back surface of the n-type single crystal silicon substrate 1, the n-type single crystal silicon substrate 1 is exposed. Since the recombination of carriers in the portion is prevented and the back electrodes 8 and 9 are formed on the entire surface of the n-type amorphous silicon film 6 and the p-type amorphous silicon film 7, the n-type amorphous Carriers can be efficiently collected from the silicon film 6 and the p-type amorphous silicon film 7. Thereby, the power generation efficiency is further improved.

(Example)
In the following examples, the photovoltaic device 500c having the structure of FIG. 5 was manufactured by the method of the above embodiment, and the output characteristics were measured. Table 2 shows the conditions for producing the photovoltaic elements of the examples.

As shown in Table 2, B ₂ H ₆ gas diluted with H ₂ gas was used to form the p-type amorphous silicon film 7, and the concentration of B ₂ H ₆ with respect to SiH ₄ was set to 2%. Further, when the n-type amorphous silicon film 6 was formed, PH ₃ gas diluted with H ₂ gas was used, and the concentration of PH ₃ with respect to SiH ₄ was set to 1%.

(Comparative example)
FIG. 11 is a schematic cross-sectional view showing the structure of a photovoltaic element of a comparative example.

  As shown in FIG. 11, an i-type amorphous silicon film 105 (non-doped amorphous silicon film) and a p-type amorphous silicon film 107 are formed on the main surface (front surface) of an n-type single crystal silicon substrate 101. It is formed in order. A surface electrode 109 made of ITO is formed on the p-type amorphous silicon film 107, and a comb-shaped collector electrode 111 made of Ag is formed on the surface electrode 109.

  An i-type amorphous silicon film 104 and an n-type amorphous silicon film 106 are sequentially formed on the back surface of the n-type single crystal silicon substrate 101. A back electrode 108 made of ITO is formed on the n-type amorphous silicon film 106, and a comb-shaped collector electrode 110 made of Ag is formed on the back electrode 108. In the photovoltaic element of the comparative example, the n-type single crystal silicon substrate 101 is the main power generation layer.

  In the comparative example, a photovoltaic device having the structure of FIG. 11 was produced, and the output characteristics were measured. The conditions for producing each film of the photovoltaic element of the comparative example are the same as those of the example.

(Evaluation)
The output characteristics of the photovoltaic elements of Examples and Comparative Examples were measured. Table 3 shows the output characteristics of the photovoltaic elements of Examples and Comparative Examples.

  As shown in Table 3, the photovoltaic elements of the examples had a maximum output Pmax, an open-circuit voltage Voc, a short-circuit current Isc, and a fill factor of F.V. as compared with the photovoltaic elements of the comparative examples. F. Both were high.

  From the above, it was found that the photovoltaic elements of the examples had higher output characteristics than the photovoltaic elements of the comparative examples.

  As described above, in the photovoltaic device according to the present invention, incident light can be utilized to the maximum. Moreover, in the manufacturing method of the photovoltaic element which concerns on this invention, the said photovoltaic element can be manufactured. Therefore, the photovoltaic device according to the present invention is suitable for use as a photovoltaic device using a semiconductor junction, and the method for producing a photovoltaic device according to the present invention includes a photovoltaic device using a semiconductor junction. It is suitable for use in manufacturing elements.

(A) is a top view which shows the back surface of the photovoltaic element which concerns on 1st Embodiment, (b) is a partially expanded view of (a). It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 1st Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 2nd Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 3rd Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 4th Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 5th Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 6th Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 7th Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 8th Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element which concerns on 9th Embodiment. It is typical sectional drawing which shows the structure of the photovoltaic element of a comparative example.

Explanation of symbols

1 n-type single crystal silicon substrate 2 i-type amorphous silicon film 3 antireflection film 4, 5 i-type amorphous silicon film 6 n-type amorphous silicon film 7 p-type amorphous silicon film 8, 9 back electrode 10, 11 Collector electrode 100 Positive electrode 200 Negative electrode 300,400 Electrode 500 Photovoltaic element

Claims (8)

Comprising a crystalline semiconductor having one side and the other side;
In the first region of the one surface of the crystalline semiconductor, an intrinsic first amorphous semiconductor film, a second amorphous semiconductor film containing an impurity having one conductivity type, and a first electrode In order,
A photovoltaic element comprising a semiconductor layer containing an impurity having another conductivity type different from the one conductivity type, and a second electrode in order in the second region of the one surface of the crystalline semiconductor. . The photovoltaic device according to claim 1, wherein the crystalline semiconductor includes an impurity having the one conductivity type. The semiconductor layer is a third amorphous semiconductor film containing an impurity having the other conductivity type,
3. The photovoltaic element according to claim 1, further comprising an intrinsic fourth amorphous semiconductor film between the crystalline semiconductor and the third amorphous semiconductor film. . A common amorphous semiconductor film in which the first amorphous semiconductor film in the first region of the crystalline semiconductor and the fourth amorphous semiconductor film in the second region are continuous. The photovoltaic element according to claim 3, wherein: The first region and the second region are provided at an interval, and a protective layer is provided on the surface of the crystalline semiconductor between the first region and the second region. The photovoltaic element according to any one of claims 1 to 3. The photovoltaic element according to claim 1, wherein the semiconductor layer is a doped layer in which the second region of the crystalline semiconductor is doped with an impurity having the other conductivity type. The photovoltaic element according to claim 1, wherein substantially the entire other surface is a light incident surface. Forming an intrinsic first amorphous semiconductor film in a first region of one surface of a crystalline semiconductor containing an impurity having one conductivity type;
Forming a second amorphous semiconductor film containing an impurity having one conductivity type on the first amorphous semiconductor film;
Forming a semiconductor layer containing an impurity having another conductivity type different from the one conductivity type in the second region of the one surface of the crystalline semiconductor;
Forming a first electrode on the second amorphous semiconductor film;
And a step of forming a second electrode on the semiconductor layer.

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