# US 2014/0193943 A1 · METHOD FOR FABRICATING Cu-In-Ga-Se FILM SOLAR CELL

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- Number: US 2014/0193943 A1
- Document ID: US20140193943A1
- Status: Published application
- Kind: A1
- Application number: 14/153,028
- Filed: 2014-01-11
- Published: 2014-07-10
- Earliest claimed: 2012-07-18
- Inventors: Liuyu Lin; Zhun Zhang
- Web page: https://patentgrep.com/patent/US20140193943A1

## CPC

- H10F 71/00: Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00)
- H10F 71/128: {Annealing}
- C23C 14/0623: {Sulfides, selenides or tellurides}
- C23C 14/34: Sputtering
- C23C 14/568: {Transferring the substrates through a series of coating stations (C23C14/562 takes precedence)}
- C23C 14/5806: {Thermal treatment}
- H10F 77/126: {comprising only Group I-III-VI chalcopyrite materials, e.g. CuInSe2, CuGaSe2 or CuInGaSe2 [CIGS]}
- H10P 14/22: using physical deposition, e.g. vacuum deposition or sputtering
- H10P 14/3236: {being chalcogenide semiconducting materials not being oxides, e.g. ternary compounds}
- H10P 14/3241: {being conductive materials}
- H10P 14/3436: {being chalcogenide semiconductor materials not being oxides, e.g. ternary compounds}
- Y02E 10/541: CuInSe2 material PV cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method for fabricating a Cu—In—Ga—Se film solar cell is provided. The method comprises: a) fabricating a molybdenum back electrode on a substrate; b) fabricating a Cu—In—Ga—Se absorbing layer on the back electrode by fractional sputtering in a plurality of sputter chambers; c) performing an annealing; d) fabricating an In2Se3 or ZnS buffer layer on the Cu—In—Ga—Se absorbing layer; e) fabricating an intrinsic zinc oxide high impedance layer on the In2Se3 or ZnS buffer layer; f) fabricating an indium tin oxide film low impedance layer on the intrinsic zinc oxide high impedance layer; g) fabricating an aluminum electrode on the indium tin oxide film low impedance layer.

## Claims

### Claim 1

A method for fabricating a Cu—In—Ga—Se film solar cell, comprising:
a) fabricating a molybdenum back electrode on a substrate;
b) fabricating a Cu—In—Ga—Se absorbing layer on the molybdenum back electrode by a multi-step sputtering, wherein
the Cu—In—Ga—Se absorbing layer is fabricated by a sputter equipment, comprising: an input stage, an input chamber, a first to Nth sputtering chambers, an unloading chamber and an unloading stage, the N sputtering chambers are connected in series, an internal volume of the input chamber is less than or equal to an internal volume of each sputtering chamber, an internal volume of the unloading chamber is less than or equal to the internal volume of each sputtering chamber, a vacuum of a first sputtering chamber is not destroyed when the substrate is transmitted from the input chamber into the first sputtering chamber, a vacuum of the last sputtering chamber is not destroyed when the substrate is transmitted from the last sputtering chamber to the unloading chamber, a CuInxGa1-xSe2 alloy target is mounted in each sputtering chamber, a sputtering with any power density ranging from 2 W/cm2 to 3 W/cm2 is performed with each CuInxGa1-xSe2alloy target for 1-2 minutes, a working pressure of each sputtering chamber is 1×10−4 Torr, and a temperature of the substrate in the sputtering chamber is maintained at any temperature between 200° C. and 450° C.;
c) performing an annealing for the Cu—In—Ga—Se absorbing layer in a rapid heating mode in the unloading chamber under a temperature of 400-600° C. for 55-90 seconds so that a Ga concentration in the Cu—In—Ga—Se absorbing layer has a gradient, the Ga concentration has a maximum on a surface of the Cu—In—Ga—Se absorbing layer contacting with the molybdenum back electrode and has a minimum on the other surface of the Cu—In—Ga—Se absorbing layer;
d) fabricating an In2Se3 or ZnS buffer layer with a thickness of 80-120 nm on the Cu—In—Ga—Se absorbing layer;
e) fabricating an intrinsic zinc oxide high impedance layer with a thickness of 0.1-0.5 μm on the In2Se3 or ZnS buffer layer;
f) fabricating an indium tin oxide film low impedance layer with a thickness of 0.3-0.8 μm on the intrinsic zinc oxide high impedance layer;
g) fabricating an aluminum electrode on the indium tin oxide film low impedance layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein a thickness of the Cu—In—Ga—Se absorbing layer ranges from 1.5 μm to 2 μm.

### Claim 3 (depends on 1)

The method of claim 1, wherein in step b),
N=5;
for the CuInxGa1-xSe2 alloy target in the first sputtering chamber, x=0;
for the CuInxGa1-xSe2 alloy target in a second sputtering chamber, 0.2<x<0.4;
for the CuInxGa1-xSe2 alloy target in a third sputtering chamber, 0.4<x<0.6;
for the CuInxGa1-xSe2 alloy target in a fourth sputtering chamber, 0.6<x<0.7; and
for the CuInxGa1-xSe2 alloy target in a fifth sputtering chamber, x=0.7.

### Claim 4 (depends on 1)

The method of claim 1, wherein in step d), the In2Se3 or ZnS buffer layer is fabricated by a vacuum magnetron sputtering with an In2Se3 alloy target or a ZnS alloy target under a working pressure of 1−5×10−3 Torr in an Ar ambience, and the temperature of the substrate is maintained at a room temperature.

### Claim 5 (depends on 1)

The method of claim 1, wherein in step e), the intrinsic zinc oxide high impedance layer is fabricated by a radio frequency vacuum magnetron sputtering with an intrinsic zinc oxide target under a working pressure of 1−5×10−3 Torr with a working frequency of 400K-2 MHz in an Ar ambience, and the temperature of the substrate is maintained at a room temperature.

### Claim 6 (depends on 1)

The method of claim 1, wherein in step f), the indium tin oxide film low impedance layer is fabricated by a vacuum direct current magnetron sputtering with an indium tin oxide target, in which a mass ratio of In2O3 to SnO2 is 9:1, under a working pressure of 1−5×10−3 Torr in an Ar ambience mixed with 2-5% O2, and the temperature of the substrate is maintained at a room temperature.

### Claim 7 (depends on 1)

The method of claim 1, wherein N=2, 3, 4, 6, 7 or 8.

### Claim 8 (depends on 1)

The method of claim 1, wherein the gradient is a linear distribution.