JPH11274526A - CIS-based chalcopyrite structure semiconductor thin film and method for manufacturing the same, and solar cell having CIS-based chalcopyrite structure semiconductor thin film and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CIS-based chalcopyrite structure semiconductor thin film capable of forming a graded band gap structure with good reproducibility and at low cost, a method of manufacturing the same, and a CI
Provided are a solar cell having an S-based chalcopyrite structure semiconductor thin film and a method for manufacturing the same. SOLUTION: In a CIS-based chalcopyrite structure semiconductor thin film having a large band gap energy near a substrate and having a small band gap energy near a film surface which comes into contact with an n-type semiconductor, an atomic ratio Al / (In + Al) is the atomic ratio Al on the film surface
Al and In so as to be smaller than / (In + Al).
Is continuously changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CIS-based chalcopyrite structure semiconductor thin film, a method of manufacturing the same, and a CIS.
The present invention relates to a solar cell having a chalcopyrite structure semiconductor thin film and a method for manufacturing the same.

[0002]

2. Description of the Related Art A compound semiconductor thin film comprising a group Ib element, a group IIIb element and a group VIb element of the periodic table is known as CIS.
It is known in the art as a compound semiconductor thin film having a system chalcopyrite structure. Such compound semiconductor thin films include, for example, CuInSe ₂ , CuInS ₂ , Cu (I
n _1-x Ga _x ) Se ₂ , CuIn (S _x Se _1-x ) ₂ , Cu
It is composed of a compound such as (In _1-x Ga _x ) (S _y Se _1-Y ) ₂ . A compound semiconductor thin film composed of these compounds is called a CIS-based compound semiconductor thin film, and is used as a light absorbing layer of a thin-film solar cell.

A method for producing such a CIS-based compound semiconductor thin film is disclosed in Japanese Patent Application Laid-Open No. 61-237476. According to the method for manufacturing a CIS-based compound semiconductor thin film, first, a thickness of 1.0 to
A Mo thin film of 1.5 μm is formed by sputtering. A thickness of about 3000 is formed on the substrate on which the Mo thin film is formed.
A layer containing Cu is formed by electrodeposition.
A layer containing In with a thickness of about 3000 is formed by electrodeposition on the layer containing In. The laminate thus obtained is placed in a diffusion furnace and sufficiently heated at about 400 ° C.

FIG. 6 is an explanatory view of a diffusion furnace used here. In FIG. 6, reference numeral 20 denotes a diffusion furnace. The diffusion furnace 20 includes a first chamber 21 and a second chamber 22, and a baffle 23 is provided between these chambers. Second
In the chamber 22, a large number of samples (the laminate) 24 are heated. In this heating step, Ar gas is supplied to the first chamber 2.
It is sent from the first chamber to the second chamber. 25 is a container which contains the individual Se. The individual Se is heated to about 200 ° C. and vaporized. Therefore, Se is mixed with Ar gas in the second chamber 2.
Sent to 2.

The laminate is placed in a diffusion furnace for about 400 hours.
When heated to ° C., Cu and In diffuse rapidly between layers containing them, but the Mo thin film of the back electrode does not change. Further, since the layer containing Cu and the layer containing In are exposed to the atmosphere having reactive Se in the second chamber 22, the reactive Se diffuses into the layer containing Cu and the layer containing In, It will react with Cu and In. Therefore, C
When the reaction proceeds, the layer containing u and the layer containing In
It results in a homogeneous layer of CuInSe ₂ of μm. in this way,
The thickness of the homogeneous layer of CuInSe ₂ is equal to the total thickness of the original Cu-containing layer and the In-containing layer (about 3000 約 + about 300
The thickness is larger than 0 °) because the reactive Se is added to include about 50 atomic% of the final semiconductor material.

Since such a semiconductor made of CuInSe ₂ has a low bandgap energy of 1.04 eV, adding Ga increases the bandgap energy to 1.4 to 1.50 eV, which is optimal for a solar cell. Attempts have been made to do so. For example, Miguel A. Con at the 1st WCPEC held on December 5-9, 1994
“HIGH EFFICIENCY Cu (In, Ga) Se ₂ announced by treras et al.
-BASED SOLAR CELLS: PROCESSING OF NOVEL ABSORBER ST
RUCTURERS ”, pages 68 to 75, describe Cu (In, Ga) in which the bandgap energy is high near the substrate and low near the surface that comes into contact with the n-type semiconductor. It has been shown that the composition of Ga and In contained in the chalcopyrite-structured semiconductor thin film is changed in order to obtain a chalcopyrite-structured semiconductor thin film composed of Se _2. Such a band gap structure is graded. It is called a bandgap structure, and attempts to reduce the recombination of carriers by tilting the conductor of the band structure and to effectively extract current.

[0007]

Conventional attempts to increase the bandgap energy in CIS-based compound semiconductors include CuIn _x Ga _{1 -x} Se ₂ (for example,
Most of the semiconductors are made of a solid solution of CuInSe ₂ and CuGaSe ₂ ). However, such a C
In the production of a semiconductor thin film made of uIn _x Ga _1-x Se ₂ , since Ga tends to migrate to the substrate side during the reaction, it is difficult to control the gradient composition of Ga, and therefore, a graded band gap structure is required. There is a problem that it is difficult to form with good reproducibility. In addition, since Ga is a relatively expensive metal, when a semiconductor thin film made of CuIn _x Ga _{1 -x} Se ₂ capable of forming a graded band gap structure is used as a light absorption layer of a solar cell, There is a problem of increasing the manufacturing cost.

An object of the present invention is to solve such a problem. That is, the present invention provides a CIS-based chalcopyrite-structured semiconductor thin film capable of forming a graded bandgap structure with good reproducibility and at low cost, a method of manufacturing the same, a solar cell having a CIS-based chalcopyrite-structured semiconductor thin film, and manufacturing thereof The aim is to provide a method.

[0009]

[Means for Solving the Problems]

The present inventor has reported that in a CIS-based chalcopyrite structure semiconductor thin film, Ga in which Al was conventionally used was used.
As described above, the inventors have found that it is easy to control the gradient composition because there is no tendency to shift to the substrate side during the reaction, and have completed the present invention.

That is, in order to achieve the above object, the first aspect of the present invention provides a CIS system having a large bandgap energy near the substrate and a small bandgap energy near the film surface which comes into contact with the n-type semiconductor. In the chalcopyrite structure semiconductor thin film, the atomic ratio A near the substrate
1 / (In + Al) is the atomic ratio Al / (I
A CIS-based chalcopyrite structure semiconductor thin film wherein the composition of Al and In is continuously changed so as to be smaller than (n + Al).

The second invention is characterized in that (A) AlSe _y is formed on a substrate.
(0 ≦ y ≦ 1.5) InSe x (0 ≦ x after film was formed
≦ 1.5) A film is formed or Al _a In _{b
Se c (0 ≦ c / (} a + b) ≦ 1.5) film process for forming a (b) the (b) on the film formed by the steps, the atomic ratio in the film 1.0 ≦ Cu /(In+Al)≦1.2 so that the metal Cu film is formed of Cu alone or metal C
forming a u film in the presence of Se; (c) subjecting the laminated film obtained through the above (b) process to 400-5
Heat at a temperature of 50 ° C. to obtain a Cu excess of CuIn _z Al _1-z
A step of forming a Se ₂ (0 <z <1) film;
Excessive CuIn _z Al ₁ -z Se ₂ (0
<Z <1) On the film, the atomic ratio in the film is 0.8 ≦ Cu /
AlSe _x (0) such that (In + Al) ≦ 1.0.
≦ x ≦ 1.5) a step of forming a film, and (e) stacking the laminated film obtained through the step (d) in the selenium atmosphere again for 400 to
A method of manufacturing a CIS-based chalcopyrite structure semiconductor thin film, comprising a step of heating at a temperature of 550 ° C.

The third invention is the second invention, wherein the AlS
_{e y (0 ≦ y ≦ 1.5} ) film and InSe _x (0 ≦ _x ≦
1.5) consisting of film laminated film, or, Al _a In _b Se _c
(0 ≦ c / (a + b) ≦ 1.5), wherein the film is amorphous (where x = 0, y =
0, c / (a + b) = 0).

According to a fourth aspect of the present invention, in the second or third aspect,
AlSe _y (0 ≦ y ≦ 1.5) film and InSe _x (0 ≦
x ≦ 1.5) A laminated film composed of a film or Al _a In _b Se
_c When forming a (0 ≦ c / (a + b) ≦ 1.5) film,
The method is characterized in that the substrate is maintained at a temperature between room temperature and 250 ° C.

[0015] The fifth invention, in the first, second or third _{invention, Al a In b Se c (} 0 ≦ c / (a + b) ≦ 1.5)
The film is formed such that the atomic ratio Al / (In + Al) near the substrate is smaller than the atomic ratio Al / (In + Al) on the film surface.

The sixth invention is characterized in that, in the second, third, fourth or fifth invention, the CIS-based chalcopyrite structure semiconductor thin film is manufactured in the same vacuum system.

According to a seventh aspect of the present invention, in the second, third, fourth, fifth or sixth aspect, the selenium atmosphere is formed by evaporating selenium from selenium alone.

The eighth invention is a CIS-based chalcopyrite structure semiconductor thin film having a large band gap energy near the substrate and a small band gap energy near the film surface which comes into contact with the n-type semiconductor. A CIS-based chalcopyrite structure semiconductor thin film in which the composition of Al and In is continuously changed such that the atomic ratio Al / (In + Al) in the vicinity is smaller than the atomic ratio Al / (In + Al) on the film surface. What is claimed is a solar cell.

According to a ninth invention, a cadmium sulfide layer is formed by a solution growth method or a vacuum evaporation method on a CIS-based chalcopyrite structure semiconductor thin film obtained by any one of the second to seventh inventions, Further, there is provided a method for manufacturing a solar cell, wherein a zinc oxide layer is formed thereon by a sputtering method.

BEST MODE FOR CARRYING OUT THE INVENTION

The substrate used in the present invention is, for example, soda lime glass, but a heat-resistant substrate such as a ceramic substrate conventionally used in the manufacture of solar cells is also used unless it is contrary to the object of the present invention. be able to.

In order to make the compound semiconductor manufactured according to the present invention into a solar cell, for example, a cadmium sulfide layer having a thickness of 30 to 500 nm as an N-type semiconductor is formed on a CIS thin film layer of the compound semiconductor by a solution growth method or a vacuum evaporation method. A zinc oxide layer having a thickness of 0.5 to 2.0 μm is formed thereon as a transparent conductive film by a sputtering method.
However, as long as the object of the present invention is not contradicted, a known cadmium sulfide layer and a means for forming a cadmium sulfide layer used in the manufacture of a solar cell can be used.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of a manufacturing process of a CIS-based chalcopyrite structure semiconductor thin film for explaining one embodiment of the present invention. FIG. 2 is an explanatory view of a manufacturing process of a CIS-based chalcopyrite structure semiconductor thin film for explaining another embodiment of the present invention. FIG. 3 is an explanatory diagram of a manufacturing process of a solar cell for explaining one embodiment of the present invention.

(Embodiment 1) This embodiment will be described with reference to FIG. Soda lime glass in which Mo was formed to a thickness of about 1 μm by sputtering was prepared as the substrate 1. Mo has p-type conduction CI when a solar cell is made.
Since an ohmic contact with the S-based chalcopyrite semiconductor thin film can be obtained and furthermore, it is difficult to react with Se, Mo was previously deposited on soda lime glass. An AlSe film 2 is formed on the substrate 1 by vacuum evaporation.
Deposition was performed at a substrate heating temperature of 200 ° C. from a binary source of 1 and Se. An InSe film 3 was deposited on the AlSe film 2 at a substrate heating temperature of 200 ° C. from a binary source of Al and Se by the same vacuum evaporation method. The total thickness of these two layers was 1 μm. Next, Cu is deposited on the AlSe film 3.
The film 4 was formed by a vacuum evaporation method without heating the substrate. [FIG. 1 (a)]

The laminated film thus formed is subjected to a Se atmosphere.
Excess Cu by heat treatment at 500 ° C for 1 hour in an atmosphere
CuIn_1-zAl_zSe_Two Film 5 was formed. After heat treatment
The atomic composition (atomic%) of the film was measured by X-ray fluorescence analysis.
As a result, Cu: In: Al: Se = 24.4: 17.
3: 2.3: 58.0. This Cu excess Cu _z 
Al_1-zSe_TwoAn AlSe film 6 is formed on the film by a vacuum evaporation method.
Filmed. [FIG. 1 (b)]

The laminated film thus formed was again heat-treated at 500 ° C. for 1 hour in a Se atmosphere to form a CIS-based chalcopyrite structure semiconductor thin film 7. [FIG.
(C)]

When the atomic composition (atomic%) of the CIS-based chalcopyrite-structured semiconductor thin film 7 was measured by X-ray fluorescence analysis, Cu: In: Al: Se = 23.2: 2.
1.8: 3.0: 52.0. In addition, the CIS
Auger electron analysis (AES) of the system chalcopyrite structure semiconductor thin film 7 resulted in the results shown in FIG. Further, when the change in the atomic ratio Al / (In + Al) in the depth direction of the CIS-based chalcopyrite-structured semiconductor thin film 7 was measured, the result shown in FIG. 5 was obtained. Further, from FIG. 5, it is found that the conduction band in which the Al content is large near the surface, lowers once inside the film, and gradually increases toward the Mo interface becomes a V-shaped atom. It was found that the composition had changed.

(Embodiment 2) This embodiment will be described with reference to FIG. Soda lime glass in which Mo was formed to a thickness of about 1 μm by sputtering was prepared as the substrate 8. An In _1-x Al _x Se film 9 was deposited on the substrate 8 from a ternary source of In, Al and Se at a substrate heating temperature of 150 ° C. by a vacuum deposition method. At this time, the film was formed by controlling the heating temperature of the vapor deposition source so that Al was large near the Mo film and In was large near the surface. This In _1-x Al _x Se
The thickness of the film 9 was 1 μm. Next, this In _1-x A
A Cu film 10 was formed to a thickness of 1 μm on the l _x Se film 9 by vacuum evaporation without heating the substrate. [FIG. 2 (a)]

The laminated film thus formed was heated at 450 ° C. for 30 minutes in a Se atmosphere to form a Cu-excessive CuIn ₁ -z Al _z Se ₂ film 11. When the atomic composition (atomic%) of the film after the heat treatment was measured by fluorescent X-ray analysis, Cu: In: Al: Se = 21.6: 1.
7.4: 2.2: 58.8. This Cu excess C
A is formed on the uIn _1-z Al _z Se ₂ film 11 by a vacuum evaporation method.
An lSe film 12 was formed. [FIG. 2 (b)]

The laminated film thus formed was heated again at 530 ° C. for 1 hour in a Se atmosphere to form a CIS-based chalcopyrite structure semiconductor thin film 13. [FIG. 2 (c)]

When the atomic composition (atomic%) of the CIS-based chalcopyrite-structured semiconductor thin film 13 was measured by X-ray fluorescence analysis, Cu: In: Al: Se = 23.4: 2.
2.3: 2.8: 51.5. In addition, the CIS
When the system chalcopyrite structure semiconductor thin film 7 was subjected to Auger electron analysis (AES), almost the same results as those shown in FIG.

(Embodiment 3) This embodiment will be described with reference to FIG. On the CIS-based chalcopyrite structure semiconductor thin film 7 obtained in Example 1, a CdS film 14 was formed to a thickness of 0.3 μm at a substrate heating temperature of 200 ° C. by a vacuum evaporation method. On this CdS film 14, a ZnO film 15 was formed to a thickness of 0.3 μm by sputtering, and subsequently, an Al-doped ZnO film 16 was formed to a thickness of 0.8 μm by sputtering to obtain a solar cell. The energy conversion of the solar cell was measured by irradiating the solar cell with light of 0.1 W / cm ₂ using a solar simulator. The measurement result showed that the open-circuit voltage was 530 mV, the short-circuit current density was 32 mA /
cm ₂ , fill factor; 52%, and energy conversion rate: 8.8%.

(Comparative Example 1) On a soda-lime glass substrate
A Mo film was formed to a thickness of 1 μm as an electrode, and an In-
The Ga-Se film is formed from ternary sources of In, Ga and Se.
Film by a vacuum evaporation method, and further a Cu film is sputtered thereon.
The film was formed by coating. The laminated film formed in this manner is
Heat treatment at 500 ° C for 1 hour in atmosphere
n_1-xGa_xSe_Two A thin film was formed. The film thickness is 2 μm
Met. This CuIn_1-xGa_xSe _Two Cd on the thin film
An S film was formed to a thickness of 0.3 μm by a vacuum evaporation method. Next
Then, a ZnO film 15 is sputtered on the CdS film.
To a thickness of 0.3 μm, followed by Al doping
0.8μm thick ZnO film formed by sputtering
And a solar cell. This conventional solar cell is
0.1W / cm_Two Solar cell under light irradiation
Measured the energy conversion rate of
Is open voltage; 520 mV, short circuit current density: 31.5 m
A / cm_Two , Fill factor; 50% and energy
Energy conversion rate: 8.2%.

Hereinafter, the operation of the present invention will be described as follows. (1) About the First Invention In a CIS-based chalcopyrite structure semiconductor thin film having a large bandgap energy near a substrate and a small bandgap energy near a film surface which comes into contact with an n-type semiconductor, an atom near a substrate is provided. Number ratio Al / (I
n + Al) is the atomic ratio Al / (In + A) on the film surface.
By continuously changing the composition of Al and In so as to be smaller than 1), a graded band gap structure can be formed with good reproducibility and low cost. The reason for this is that Al used here does not tend to migrate to the substrate side during the reaction, unlike Ga conventionally used, so that the gradient composition can be easily controlled and the price is relatively low. This is because it is a suitable metal.

(2) Regarding the second invention, if a large amount of Al is present near the substrate in the step (a), CuA
1Se ₂ is generated. CuAlSe ₂ is a conventional CuA
Since the band gap energy is larger than 1Se ₂ , in the first invention, the conduction band has a graded band gap structure.

Further, by allowing Al to be present in the vicinity of the surface in the steps (d) and (e), the Miguel A. Co.
“HIGH EFFICIENCY Cu (In, Ga) Se
₂ -BASED SOLAR CELLS: PROCESSING OF NOVEL ABSORBER
As described in “STRUCTURERS”, a V-shaped conductor is formed. When the conductor is formed in a V-shaped structure, the spectral sensitivity in a long wavelength region such as 1100 to 1200 nm is increased. Better, the short circuit current is improved,
Since the bandgap energy approaches an ideal value, the open-circuit voltage can be improved.

In the step (b), the ratio of the number of atoms in the film is set to 1.0 ≦ C
If u / (In + Al) ≦ 1.2 and Cu is excessive,
During the heating in the step (e), excess Cu-Se becomes a liquid phase, which acts as a flux at the time of crystal growth, thereby improving the crystallinity. In addition, the value of 1.2 or less is
If it is more than this, Al is relatively large. CuAl _1-z Se
₂ (0 <z <1) is formed considerably in the vicinity of the surface. Therefore, when this thin film is used as a light absorption band of a solar cell, the open-circuit voltage characteristics are improved, but the carrier is formed of a V-shaped conductor. This is because some of them are trapped for a long time, so that the recombination of carriers increases, and as a result, a large amount of current cannot be taken out.

In the steps (a) and (e), the heating temperature is 400
If the temperature is lower than 400 ° C., a complete chalcopyrite crystal structure is not formed.
This is because a different phase such as In-Se, Al-Se, or Cu-Se may remain. The temperature is set lower than 550 ° C. for the following reason. Such a chalcopyrite-structured semiconductor thin film is often used as a light absorbing layer of a solar cell, and in most cases, soda lime glass is used as a substrate of the solar cell. This is because, when the substrate is heated, alkali metals such as Na and K supplied from soda lime glass are doped into the light absorbing layer, the carrier concentration is increased, and the solution voltage characteristics of the solar cell are mainly improved and the energy conversion rate is improved. It is thought that it is. The softening point of soda-lime glass is around 570 ° C., but depending on the stress of the film formed as the back electrode on the soda-lime glass, the substrate may warp at a slightly lower temperature than this.
From the experience of the present inventors, it has been found that a CIS-based chalcopyrite structure semiconductor thin film having no substrate deformation and a good crystallinity can be obtained at a temperature up to 550 ° C.

[0038] (3) The third invention for AlSe _y, in AlSe _x and _{Al a In b Se c, x} , y, c / (a + b) is a 0 to 1.5, the
Basically, this kind of compound has no composition exceeding 1.5. In the present invention, this value is
Preferably, it is better to be 0.8 to 1.3. If it is smaller than 0.8, the coefficient of expansion of the film increases when Cu is added and reacted at a high temperature, and a film having good adhesion cannot be obtained. On the other hand, when the ratio exceeds 1.3, the Se content is too large, and the crystallinity of the formed film deteriorates.

(4) Regarding the Fourth Invention The reason why the substrate is kept at room temperature to 250 ° C. is that a crystalline film is formed when the temperature exceeds 250 ° C.

[0040] (5) For the fifth invention _{Al a In b Se c (0} ≦ c / (a + b) ≦ 1.5) film, the atomic ratio of near substrate Al / (In + Al) is of the membrane surface A graded band cap can be formed by forming a film so that the atomic ratio becomes smaller than the atomic ratio Al / (In + Al).

(6) Regarding the Sixth Invention The manufacturing cost for manufacturing a CIS-based chalcopyrite structure semiconductor thin film in the same vacuum system can be reduced.

(7) Regarding the Seventh Invention Since the selenium atmosphere is created by evaporating selenium from selenium alone, handling is safe.

(8) An eighth aspect of the present invention is a CIS-based chalcopyrite structure semiconductor thin film having a large band gap energy near the substrate and a small band gap energy near the film surface which comes into contact with the n-type semiconductor. , The atomic number ratio Al / (I
n + Al) is the atomic ratio Al / (In + A) on the film surface.
Providing a low-cost solar cell with improved energy conversion efficiency by having a CIS-based chalcopyrite structure semiconductor thin film in which the composition of Al and In is continuously changed so as to be smaller than 1) as a light absorbing layer. can do.

(9) Regarding the Ninth Invention The C obtained by any one of the first to sixth inventions
Energy conversion efficiency was improved by forming a cadmium sulfide layer on the IS-based chalcopyrite structure semiconductor thin film by solution growth method or vacuum evaporation method, and further forming a zinc oxide layer on the cadmium sulfide layer by sputtering method. A solar cell can be provided.

[0045]

Industrial Applicability A CIS-based chalcopyrite-structured semiconductor thin film capable of forming a graded band gap structure with good reproducibility and at low cost, a method of manufacturing the same, and a solar cell having the CIS-based chalcopyrite-structured semiconductor thin film and a method of manufacturing the same Can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a manufacturing process of a CIS-based chalcopyrite structure semiconductor thin film for explaining one embodiment of the present invention.

FIG. 2 is a CIS for explaining another embodiment of the present invention;
It is explanatory drawing of the manufacturing process of a system chalcopyrite structure semiconductor thin film.

FIG. 3 is an explanatory view of a manufacturing process of a solar cell for explaining one embodiment of the present invention.

FIG. 4 shows Auger electron analysis (A) of a CIS-based chalcopyrite structure semiconductor thin film manufactured according to an embodiment of the present invention.
ES) A graph showing the results.

FIG. 5 is an atomic ratio Al / (In) of a CIS-based chalcopyrite structure semiconductor thin film manufactured according to an embodiment of the present invention.
12 is a graph showing the change in the depth direction of (+ Al) measured.

FIG. 6 is an explanatory diagram of a diffusion furnace used in manufacturing a conventional CIS-based compound semiconductor thin film.

[Explanation of symbols]

Reference Signs List 1,8 Substrate 2,6,12 AlSe film 3 InSe film 4,10 Cu film 5,11 CuIn _1-z Al _z Se ₂ film 7,13 CIS chalcopyrite structure semiconductor thin film 9 In _1-z Al _z Se ₂ Film 14 CdS film 15 ZnO film 16 Al-doped ZnO film

Claims (9)

[Claims] In a CIS-based chalcopyrite structure semiconductor thin film having a large band gap energy near a substrate and a small band gap energy near a film surface which comes into contact with an n-type semiconductor, an atomic ratio Al near a substrate is obtained. / (In + Al) is the atomic ratio Al of the film surface
Al and In so as to be smaller than / (In + Al).
A CIS-based chalcopyrite structure semiconductor thin film, wherein the composition of the compound is continuously changed. (2) AlSe on the substrate_y (0 ≦ y ≦ 1.
5) After forming the film, InSe_x (0 ≦ x ≦ 1.5)
Film or Al on the substrate_aIn_bSe _c (0 ≦ c
/(A+b)≦1.5) a step of forming a film;
So that 1.0 ≦ Cu / (In + Al) ≦ 1.2,
Either a metal Cu film is formed with Cu alone or a metal Cu film
Forming a film in the presence of Se. (C) placing the laminated film obtained through the step (b) in a selenium atmosphere
Heating at a temperature of 400 to 550 ° C.
In_zCuAl_1-zSe_Two (0 <z <1) film forming process
(D) Cu-excessive CuIn obtained through the step (c)_zAl
_1-zSe_Two (0 <z <1) On the film, the atomic ratio in the film is
So that 0.8 ≦ Cu / (In + Al) ≦ 1.0,
AlSe_x (E) a step of forming a film (0 ≦ x ≦ 1.5);
Heating at a temperature of 400 to 550 ° C. in the CIS chalcopyrite
Manufacturing method of structural semiconductor thin film. 3. An AlSe _y (0 ≦ y ≦ 1.5) film and I
a laminated film composed of an nSe _x (0 ≦ x ≦ 1.5) film, or
_{Al a In b Se c (0} ≦ c / (a + b) ≦ 1.5) C according to claim 2, wherein the film is characterized in that an amorphous
A method for producing an IS-based chalcopyrite-structured semiconductor thin film (except when x = 0, y = 0, and c / (a + b) = 0). 4. An AlSe _y (0 ≦ y ≦ 1.5) film and I
a laminated film composed of an nSe _x (0 ≦ x ≦ 1.5) film, or
The _{Al a In b Se c (0} ≦ c / (a + b) ≦ 1.5) film in formation, CIS system according to claim 2 or 3, wherein the holding substrate to room temperature to 250 DEG ° C. A method for producing a chalcopyrite structure semiconductor thin film. 5. _{Al a In b Se c (0} ≦ c / (a + b)
.Ltoreq.1.5), and the atomic ratio Al / (In)
+ Al) is the atomic ratio Al / (In + Al) on the film surface
5. The method for producing a CIS-based chalcopyrite structure semiconductor thin film according to claim 2, wherein the film is formed so as to be smaller than the above. 6. The method of manufacturing a CIS-based chalcopyrite-structured semiconductor thin film according to claim 2, wherein the CIS-based chalcopyrite-structured semiconductor thin film is manufactured in the same vacuum system. 7. The method for producing a CIS-based chalcopyrite structure semiconductor thin film according to claim 2, wherein the selenium atmosphere is formed by evaporating selenium from selenium alone. 8. A CIS-based chalcopyrite structure semiconductor thin film having a large band gap energy near a substrate and a small band gap energy near a film surface which comes into contact with an n-type semiconductor, wherein the number of atoms in the vicinity of the substrate is small. The ratio Al / (In + Al) is the atomic ratio Al of the film surface.
Al and In so as to be smaller than / (In + Al).
A solar cell comprising a CIS-based chalcopyrite-structured semiconductor thin film in which the composition of C is continuously changed. 9. A cadmium sulfide layer is formed on the CIS-based chalcopyrite-structured semiconductor thin film obtained by the method according to claim 2 by a solution growth method or a vacuum evaporation method. And forming a zinc oxide layer thereon by sputtering.