# US 9,040,113 B2 · Atomic layer deposition of metal sulfide thin films using non-halogenated precursors

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- Number: US 9,040,113 B2
- Document ID: US9040113B2
- Status: Granted
- Kind: B2
- Application number: 12/780,664
- Filed: 2010-05-14
- Published: 2010-12-02
- Granted: 2015-05-26
- Earliest claimed: 2009-05-26
- Assignees: Uchicago Argonne, LLC
- Applicants: Alex B. F. Martinson; Jeffrey W. Elam; Michael J. Pellin
- Inventors: Alex B. F. Martinson; Jeffrey W. Elam; Michael J. Pellin
- Web page: https://patentgrep.com/patent/US9040113B2

## CPC

- H10P 14/2925: {Surface structures}
- C23C 16/305: {Sulfides, selenides, or tellurides}
- C23C 16/45553: {characterized by the use of precursors specially adapted for ALD}
- H10F 10/16: Photovoltaic cells having only PN heterojunction potential barriers
- H10F 77/12: Active materials
- H10F 77/148: {Shapes of potential barriers}
- H10F 77/211: {for photovoltaic cells}
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/3428: {Sulfides}
- H10P 14/3436: {being chalcogenide semiconductor materials not being oxides, e.g. ternary compounds}
- Y02E 10/50: Photovoltaic [PV] energy
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- 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)
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method for preparing a metal sulfide thin film using ALD and structures incorporating the metal sulfide thin film. The method includes providing an ALD reactor, a substrate, a first precursor comprising a metal and a second precursor comprising a sulfur compound. The first and the second precursors are reacted in the ALD precursor to form a metal sulfide thin film on the substrate. In a particular embodiment, the metal compound comprises Bis(N,N′-di-sec-butylacetamidinato)dicopper(I) and the sulfur compound comprises hydrogen sulfide (H2S) to prepare a Cu2S film. The resulting metal sulfide thin film may be used in among other devices, photovoltaic devices, including interdigitated photovoltaic devices that may use relatively abundant materials for electrical energy production.

## Claims

### Claim 1

A method for preparing a portion of an interdigitated photovoltaic device, comprising:
providing an atomic layer deposition (ALD) reactor;
providing a high-aspect ratio substrate;
providing a first non-halogenated precursor comprising Bis(N,N′-di-sec-butylacetamidinato)dicopper(I);
providing a second non-halogenated precursor comprising a sulfur compound;
reacting the first non-halogenated precursor in the ALD reactor for a first period;
reacting the second non-halogenated precursor in the ALD reactor for a second period;
repeating the reactions of the first non-halogenated precursor and the second non-halogenated precursor for a number of cycles until a chalcocite film of a desired thickness is formed on the high-aspect ratio substrate.

### Claim 2 (depends on 1)

The method of claim 1, wherein the second non-halogenated precursor comprises H2S.

### Claim 3 (depends on 2)

The method of claim 2, wherein the chalcocite film consists essentially of Cu2S.

### Claim 4 (depends on 1)

The method of claim 1, wherein the chalcocite film consists essentially of a copper sulfide.

### Claim 5 (depends on 4)

The method of claim 4, wherein the copper sulfide is selected from the group of CuxS, where x is about 1.8-2.2.

### Claim 6 (depends on 1)

The method of claim 1, wherein the chalcocite film is deposited on a transparent oxide conductor (TCO) electrode coupled to the high-aspect ratio substrate, and wherein the chalcocite film is further coupled to a n-type semiconductor.

### Claim 7 (depends on 6)

The method of claim 6, further comprising preparing an interdigitated photovoltaic device using the high-aspect ratio substrate.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
providing a purge gas; and
substantially purging the ALD reactor with the purge gas after at least one of the first period and the second period.

### Claim 9

A method for preparing a Cu2S film on a substrate, comprising:
providing an atomic layer deposition (ALD) reactor;
providing a substrate;
providing a first non-halogenated precursor, the first precursor comprising Bis(N,N′-di-sec-butylacetamidinato)dicopper(I);
providing a second non-halogenated precursor, the second precursor comprising H2S;
heating the substrate to a reaction temperature;
exposing the substrate in the ALD reactor to the first non-halogenated precursor for a first predetermined duration;
exposing the substrate in the ALD reactor to the second non-halogenated precursor for a second predetermined duration;
repeating for a predetermined number of cycles exposure of the substrate in the ALD reactor to the first non-halogenated precursor and the second non-halogenated precursor to form a Cu2S film on the substrate.

### Claim 10 (depends on 9)

The method of claim 9, further comprising:
providing a purge gas; and
substantially purging the ALD reactor with the purge gas after at least one of the first predetermined duration and the second predetermined duration.

### Claim 11 (depends on 9)

The method of claim 9, wherein the substrate comprises a high-aspect ratio substrate.

### Claim 12

A method for preparing a portion of an interdigitated photovoltaic device, comprising:
providing an atomic layer deposition (ALD) reactor;
providing a high-aspect ratio substrate;
providing a first non-halogenated precursor comprising Bis(N,N′-di-sec-butylacetamidinato)dicopper(I);
providing a second non-halogenated precursor comprising a sulfur compound;
reacting the first non-halogenated precursor in the ALD reactor for a first period;
reacting the second non-halogenated precursor in the ALD reactor for a second period; and
repeating the reactions of the first non-halogenated precursor and the second non-halogenated precursor for a number of cycles until a chalcocite film of a desired thickness is formed on the high-aspect ratio substrate;
wherein an average growth rate of the chalcocite film of at least about 0.9 Å per cycle is achieved.

### Claim 13 (depends on 12)

The method of claim 12, wherein the second non-halogenated precursor comprises H2S.

### Claim 14 (depends on 12)

The method of claim 12, wherein the chalcocite film consists essentially of a copper sulfide.

### Claim 15 (depends on 14)

The method of claim 14, wherein the copper sulfide is selected from the group of CuxS, where x is about 1.8-2.2.

### Claim 16 (depends on 12)

The method of claim 12, wherein the chalcocite film is deposited on a transparent oxide conductor (TCO) electrode coupled to the high-aspect ratio substrate, and wherein the chalcocite film is further coupled to a n-type semiconductor.

### Claim 17 (depends on 16)

The method of claim 16, further comprising preparing an interdigitated photovoltaic device using the high-aspect ratio substrate.