Combinatorial Screening of Transparent Conductive Oxide Materials for Solar Applications

• US 20120238050A1
• Filed: 04/30/2012
• Published: 09/20/2012
• Est. Priority Date: 06/02/2009
• Status: Active Grant

• Current Assignee: Guizhen Zhang, Minh Anh Nguyen, Nikhil Kalyankar, Nitin Kumar, Zhiwen Sun
• Original Assignee: Guizhen Zhang, Minh Anh Nguyen, Nikhil Kalyankar, Nitin Kumar, Zhiwen Sun
• Inventors: Sun, Zhi-Wen, Kumar, Nitin, Zhang, Guizhen, Kalyankar, Nikhil, Nguyen, Minh Anh
• Granted Patent: US 8,492,189 B2
• Time in Patent Office: Days
• US Class Current: 438/71
• CPC Class Codes: B01J 19/0046 Sequential or parallel reactions, e.g. for the synthesis of polypeptides or polynucleotides; Apparatus and devices for combinatorial chemistry or for making molecular arrays synthesis methods per se C40B50/00
• CPC Class Codes: B01J 2219/0043 for direct application of reagents, e.g. through openings in a shutter
• CPC Class Codes: B01J 2219/00443 Thin film deposition
• CPC Class Codes: B01J 2219/00536 in the shape of disks
• CPC Class Codes: B01J 2219/00596 Solid-phase processes
• CPC Class Codes: B01J 2219/00702 Processes involving means for analysing and characterising the products
• CPC Class Codes: B01J 2219/00754 Metal oxides
• CPC Class Codes: B01J 2219/00756 Compositions, e.g. coatings, crystals, formulations
• CPC Class Codes: C40B 40/18 Libraries containing only inorganic compounds or inorganic materials
• CPC Class Codes: C40B 60/14 for creating libraries
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/02366 of the substrate or of a layer on the substrate, e.g. textured ITO/glass substrate or superstrate, textured polymer layer on glass substrate
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

Embodiments of the current invention include methods of improving a process of forming a textured TCO film by combinatorial methods. The combinatorial method may include depositing a TCO by physical vapor deposition or sputtering, annealing the TCO, and etching the TCO where at least one of the depositing, the annealing, or the etching is performed combinatorially. Embodiments of the current invention also include improved methods of forming the TCO based on the results of combinatorial testing.

Claims

1. A combinatorial method, comprising:

depositing a transparent conductive oxide (TCO) film by physical vapor deposition, wherein depositing the TCO comprises a site-isolated deposition to form site-isolated regions on a single substrate through the physical vapor deposition, each site isolated region having a uniform composition of zinc oxide;

annealing the TCO film;

forming a molecular masking layer on the TCO film, the molecular mask allowing for differential texturing, wherein forming the molecular masking layer comprises applying an etching formulation to the surface of the TCO film; and

etching the TCO film to provide a textured surface that scatters light incident upon the textured surface, wherein at least one of the depositing, the annealing, or the etching is performed combinatorially.

2. The combinatorial method of claim 1, wherein the annealing is performed after the etching.

3. The method of claim 1, wherein the etching is a wet etch.

4. The combinatorial method of claim 1, wherein the etching is achieved with an acidic wet chemistry.

5. The combinatorial method of claim 4, wherein the acidic wet chemistry is one of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid, oxalic acid, or carboxylic acid.

6. The combinatorial method of claim 1, further comprising:

depositing an optical conversion layer configured to transform incident light into electrical energy over the textured surface of the TCO film; and

depositing a conductive material over the optical conversion layer.

7. The combinatorial method of claim 6, wherein the site-isolated deposition comprises placing a physical mask on the substrate and depositing the TCO film over the physical mask.

8. The combinatorial method of claim 7, further comprising varying the depositing between the site-isolated regions.

9. The combinatorial method of claim 8, wherein varying the depositing between the site-isolated regions comprises varying a deposition temperature.

10. The combinatorial method of claim 1, wherein the etching is performed in a site-isolated manner to form site-isolated regions.

11. The combinatorial method of claim 10, further comprising varying the etching between site-isolated regions.

12. The combinatorial method of claim 11, wherein varying the etching between site-isolated regions comprises varying the etching chemistries.

13. The combinatorial method of claim 1, wherein annealing in a combinatorial manner comprises varying the annealing temperature.

14. The combinatorial method of claim 1, wherein annealing in a combinatorial manner comprises varying the gas ambient within an annealing chamber during the annealing.

15. A method of forming a solar substrate, comprising:

depositing a transparent conductive oxide (TCO) layer on a substrate by physical vapor deposition (PVD) at a temperature of less than 250°

C.;

annealing the TCO at a temperature of greater than 200°

C.;

forming a molecular masking layer on the TCO the molecular mask allowing for differential texturing, wherein forming the molecular masking layer comprises applying an etching formulation to the surface of the TCO; and

etching the TCO to provide a textured surface that scatters light incident upon the textured surface;

depositing an optical conversion layer configured to transform incident light into electrical energy over the textured surface of the TCO; and

depositing a conductive material over the optical conversion layer.

16. The method of claim 15, further comprising etching the TCO with a wet chemistry to texture a surface of the TCO in an irregular pattern.

17. The method of claim 15, wherein depositing the transparent conductive oxide (TCO) on a substrate by physical vapor deposition (PVD) is done at room temperature.

18. The method of claim 15, wherein annealing the TCO comprises annealing the TCO at a temperature in the approximate range of 250°

C.-350°

C.

19. The method of claim 15, wherein annealing the TCO comprises one of conventional thermal heating or rapid thermal annealing (RTA).

20. The method of claim 15, wherein the etching is performed with a wet etchant.