# US 2013/0153024 A1 · Multilayer transparent electroconductive film and method for manufacturing same, as well as thin-film solar cell and method for manufacturing same

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- Number: US 2013/0153024 A1
- Document ID: US20130153024A1
- Status: Published application
- Kind: A1
- Application number: 13/818,401
- Filed: 2011-08-30
- Published: 2013-06-20
- Earliest claimed: 2010-08-30
- Assignees: Sumitomo Metal Mining Co., Ltd.
- Inventors: Yoshiyuki Abe; Kentaro Sogabe; Yasunori Yamanobe
- Web page: https://patentgrep.com/patent/US20130153024A1

## CPC

- H10F 77/251: {comprising zinc oxide [ZnO]}
- C23C 14/086: {of zinc, germanium, cadmium, indium, tin, thallium or bismuth}
- C23C 14/34: Sputtering
- H10F 71/138: {Manufacture of transparent electrodes, e.g. transparent conductive oxides [TCO] or indium tin oxide [ITO] electrodes}
- H10F 77/707: {of the substrates or of layers on substrates, e.g. textured ITO layer on a glass substrate}
- Y02E 10/50: Photovoltaic [PV] energy
- Y02E 10/548: Amorphous silicon PV cells
- Y10T 428/24355: Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
- Y10T 428/24967: Absolute thicknesses specified
- 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)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A multilayer transparent electroconductive film is obtained by stacking a transparent electroconductive film (II) on a transparent electroconductive film (I), and in this structure, the transparent electroconductive film (I) contains one or more added elements selected from aluminum and gallium, and the content of the added elements is in a range represented by −2.18×[Al]+1.74≦[Ga]≦−1.92×[Al]+6.10. The transparent electroconductive film (II) contains one or more added elements selected from aluminum and gallium, and the content of the added elements is in a range represented by −[Al]+0.30≦[Ga]≦−2.68×[Al]+1.74. In this case, [Al] is the aluminum content expressed as the atomic ratio (%) Al/(Zn+Al) and [Ga] is the gallium content expressed as the atomic ratio (%) Ga/(Zn+Ga).

## Claims

### Claim 1

A multilayer transparent electroconductive film comprising:
a transparent electroconductive film (I) mainly composed of zinc oxide; and
a transparent electroconductive film (II) mainly composed of zinc oxide, having a composition different from the composition of the transparent electroconductive film (I), which is stacked on the transparent electroconductive film (I),
wherein the transparent electroconductive film (I) contains one or more added elements selected from aluminum and gallium, with the content of the added elements being in a range represented by the following inequality (1), and the transparent electroconductive film (II) contains one or more added elements selected from aluminum and gallium, with the content of the added elements being in a range represented by the following inequality (2):
−2.18×[Al]+1.74≦[Ga]≦−1.92×[Al]+6.10 (1)
—[Al]+0.30≦[Ga]≦−2.68×[Al]+1.74 (2)
(where [Al] is the aluminum content expressed as the atomic ratio (%) Al/(Zn+Al), and [Ga] is the gallium content expressed as the atomic ratio (%) Ga/(Zn+Ga)).

### Claim 2 (depends on 1)

The multilayer transparent electroconductive film according to claim 1, wherein the transparent electroconductive film (I) has a film thickness in a range from 200 to 700 μm and the transparent electroconductive film (II) has a film thickness in a range from 300 to 2200 μm.

### Claim 3 (depends on 1)

The multilayer transparent electroconductive film according to claim 1, wherein the transparent electroconductive film (II) has a surface roughness (Ra) of 35.0 nm or more and a surface resistance of 250Ω/□ or less.

### Claim 4 (depends on 1)

The multilayer transparent electroconductive film according to claim 1, further comprising a haze ratio of 10% or more.

### Claim 5

A method for manufacturing a multilayer transparent electroconductive film having a transparent electroconductive film (I) mainly composed of zinc oxide; and a transparent electroconductive film (II) mainly composed of zinc oxide, having a composition different from the composition of the transparent electroconductive film (I), which is stacked on the transparent electroconductive film (I), comprising the steps of:
by using an oxide sintered body target that is mainly composed of zinc oxide and contains one or more added elements selected from aluminum and gallium, with the content of the added elements being in a range represented by the following inequality (3), forming the transparent electroconductive film (I) by using a sputtering method under conditions of a sputtering gas pressure in a range from 0.1 to 0.8 Pa and a substrate temperature in a range from room temperature to 400° C., and
by using an oxide sintered body target that is mainly composed of zinc oxide and contains one or more added elements selected from aluminum and gallium, with the content of the added elements being in a range represented by the following inequality (4), forming the transparent electroconductive film (II) by using a sputtering method under conditions of a sputtering gas pressure in a range from 2.0 to 15.0 Pa and a substrate temperature in a range from 300 to 600° C.:
−2.18×[Al]+1.74≦[Ga]≦−1.92×[Al]+6.10 (3)
—[Al]+0.30≦[Ga]≦−2.68×[Al]+1.74 (4)
(where [Al] is the aluminum content expressed as the atomic ratio (%) Al/(Zn+Al), and [Ga] is the gallium content expressed as the atomic ratio (%) Ga/(Zn+Ga)).

### Claim 6 (depends on 5)

The method for manufacturing a multilayer transparent electroconductive film according to claim 5, wherein after forming the transparent electroconductive film (I) and the transparent electroconductive film (II), an annealing treatment is carried thereon in vacuum or in a reducing atmosphere.

### Claim 7

A thin-film solar cell comprising:
a multilayer transparent electroconductive film, a photoelectric conversion layer unit and a back electrode layer that are successively stacked on a translucent substrate,
wherein the multilayer transparent electroconductive film comprises: a transparent electroconductive film (I) mainly composed of zinc oxide; and a transparent electroconductive film (II) mainly composed of zinc oxide, having a composition different from the composition of the transparent electroconductive film (I), which is stacked on the transparent electroconductive film (I), and
wherein the transparent electroconductive film (I) contains one or more added elements selected from aluminum and gallium, with the content of the added elements being in a range represented by the following inequality (5), and the transparent electroconductive film (II) contains one or more added elements selected from aluminum and gallium, with the content of the added elements being in a range represented by the following inequality (6):
−2.18×[Al]+1.74≦[Ga]≦−1.92×[Al]+6.10 (5)
—[Al]+0.30≦[Ga]≦−2.68×[Al]+1.74 (6)
(where [Al] is the aluminum content expressed as the atomic ratio (%) Al/(Zn+Al), and [Ga] is the gallium content expressed as the atomic ratio (%) Ga/(Zn+Ga)).

### Claim 8

A method for manufacturing a thin-film solar cell comprising: a multilayer transparent electroconductive film, a photoelectric conversion layer unit and a back electrode layer that are successively stacked on a translucent substrate, wherein the multilayer transparent electroconductive film comprises: a transparent electroconductive film (I) mainly composed of zinc oxide; and a transparent electroconductive film (II) mainly composed of zinc oxide, having a composition different from the composition of the transparent electroconductive film (I), which is stacked on the transparent electroconductive film (I), comprising the steps of:
by using an oxide sintered body target that is mainly composed of zinc oxide and contains one or more added elements selected from aluminum and gallium, with the content of the added elements being in a range represented by the following inequality (7), forming the transparent electroconductive film (I) by using a sputtering method under conditions of a sputtering gas pressure in a range from 0.1 to 0.8 Pa and a substrate temperature in a range from room temperature to 400° C., and
by using an oxide sintered body target that is mainly composed of zinc oxide and contains one or more added elements selected from aluminum and gallium, with the content of the added elements being in a range represented by the following inequality (8), forming the transparent electroconductive film (II) by using a sputtering method under conditions of a sputtering gas pressure in a range from 2.0 to 15.0 Pa and a substrate temperature in a range from 300 to 600° C.:
−2.18×[Al]+1.74≦[Ga]≦−1.92×[Al]+6.10 (7)
—[Al]+0.30≦[Ga]≦−2.68×[Al]+1.74 (8)
(where [Al] is the aluminum content expressed as the atomic ratio (%) Al/(Zn+Al), and [Ga] is the gallium content expressed as the atomic ratio (%) Ga/(Zn+Ga)).

### Claim 9 (depends on 2)

The multilayer transparent electroconductive film according to claim 2, wherein the transparent electroconductive film (II) has a surface roughness (Ra) of 35.0 nm or more and a surface resistance of 25Ω/□ or less.

### Claim 10 (depends on 2)

The multilayer transparent electroconductive film according to claim 2, further comprising a haze ratio of 10% or more.

### Claim 11 (depends on 3)

The multilayer transparent electroconductive film according to claim 3, further comprising a haze ratio of 10% or more.

### Claim 12 (depends on 9)

The multilayer transparent electroconductive film according to claim 9, further comprising a haze ratio of 10% or more.