Bulk chloride species treatment of thin film photovoltaic cell and manufacturing method

• US 8,198,122 B2
• Filed: 07/26/2011
• Issued: 06/12/2012
• Est. Priority Date: 09/29/2008
• Status: Expired due to Fees

• Current Assignee: Stion Corporation
• Original Assignee: Stion Corporation
• Inventors: Lee, Howard W. H.
• Primary Examiner(s): Vu, David
• Assistant Examiner(s): TAYLOR, EARL N
• Application Number:
  US13/190,856
• Publication Number:
  US 20110277837A1
• Time in Patent Office: 322 Days
• Field of Search: 438/85, 257E21466-E2147, 257/E21.483, 257/E21.485, 257/E21.497, 136/265
• US Class Current: 438/85
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02491 Conductive materials
• CPC Class Codes: H01L 21/02568 Chalcogenide semiconducting materials not being oxides, e.g. ternary compounds
• CPC Class Codes: H01L 21/02614 Transformation of metal, e.g. oxidation, nitridation
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 31/0322 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
• CPC Class Codes: H01L 31/0323 characterised by the doping material
• CPC Class Codes: H01L 31/0749 including a AIBIIICVI compound, e.g. CdS/CulnSe2 [CIS] heterojunction solar cells
• CPC Class Codes: H01L 31/186 Particular post-treatment for the devices, e.g. annealing, impurity gettering, short-circuit elimination, recrystallisation
• CPC Class Codes: Y02E 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A method for forming a thin film photovoltaic device. The method includes providing a transparent substrate comprising a surface region. A first electrode layer is formed overlying the surface region. A copper layer is formed overlying the first electrode layer and an indium layer is formed overlying the copper layer to form a multi-layered structure. The method subjects at least the multi-layered structure to a thermal treatment process in an environment containing a sulfur bearing species to form a bulk copper indium disulfide material. The bulk copper indium disulfide material comprises one or more portions of copper indium disulfide material and a copper poor surface region characterized by a copper-to-indium atomic ratio of less than about 0.95:1. The method subjects the copper poor surface and one or more portions of the bulk copper indium disulfide material to a chlorine species to convert the copper poor surface from an n-type characteristic to a p-type characteristic and to convert any of the one or more portions of the bulk copper indium disulfide material having the copper-to-indium atomic ratio of less than about 0.95:1 from a n-type characteristic to an p-type characteristic. A window layer is formed overlying the copper indium disulfide material.

Claims

1. A method for forming a thin film photovoltaic device comprising:

providing a substrate comprising a surface region;

forming a first electrode layer overlying the surface region;

forming a copper layer overlying the first electrode layer;

forming an indium layer overlying the copper layer to form a multi-layered structure;

subjecting at least the multi-layered structure to a thermal treatment process in an environment containing a sulfur bearing species;

forming a bulk copper indium disulfide material from the multi-layered structure, wherein the bulk copper indium disulfide material comprises a surface region characterized by a copper poor surface;

subjecting the copper poor surface and one or more portions of the bulk copper indium disulfide material to chloride species;

converting the copper poor surface from an n-type characteristic to a p-type characteristic;

converting any of the one or more portions of the bulk copper indium disulfide material from a n-type characteristic to an p-type characteristic;

forming a window layer overlying the bulk copper indium disulfide material.

2. The method of claim 1 wherein the subjecting of the chloride species is provided by at least one process selected from spin coating, spraying, spray pyrolysis, pyrolysis, dipping, deposition, sputtering, or electrolysis.

3. The method of claim 1 wherein the chloride species comprises chloride ions.

4. The method of claim 1 wherein the chloride species is derived from a cadmium chloride species.

5. The method of claim 1 wherein the bulk copper indium disulfide comprises a thickness of copper sulfide material, wherein the thickness of copper sulfide material is selectively removed using a solution of potassium cyanide.

6. The method of claim 1 wherein the window layer is selected from a group consisting of cadmium sulfide, zinc sulfide, zinc selenide, zinc oxide, and zinc magnesium oxide.

7. The method of claim 1 wherein converting the copper poor surface from an n-type characteristic to a p-type characteristic is done using a thermal treatment process characterized by a temperature ranging from about 100 Degrees Celsius to about 500 Degrees Celsius.

8. The method of claim 1 wherein the chloride species compensates for any missing copper in the copper poor surface.

9. The method of claim 1 wherein the window layer comprises an n⁺-type semiconductor characteristic.

10. The method of claim 1 further comprising introducing an indium species in the window layer to cause formation of an n⁺-type semiconductor characteristic.

11. The method of claim 1 wherein the bulk copper indium disulfide is mixed with a copper indium aluminum disulfide or copper indium gallium disulfide.

12. The method of claim 1 wherein the sulfide bearing species are obtained from hydrogen sulfide in a fluid phase.

13. A method for forming a thin film photovoltaic device, the method comprising:

providing a transparent substrate comprising a surface region;

forming a first electrode layer overlying the surface region;

forming a copper indium material by at least sputtering a target comprising an indium copper material;

subjecting the copper indium material to thermal treatment process in an environment containing a sulfur bearing species;

forming a copper-poor indium disulfide material from at least the thermal treatment process of the copper poor indium material;

compensating the copper-poor copper indium disulfide material using a chloride species, wherein the copper poor copper indium disulfide material has an n-type characteristic;

changing the copper-poor copper indium disulfide material to have a p-type characteristic; and

forming a window layer overlying the copper indium disulfide material.

14. The method of claim 13 wherein the compensating is provided by at least one process selected from spin coating, spraying, spray pyrolysis, pyrolysis, dipping, deposition, sputtering, or electrolysis.

15. The method of claim 13 wherein the chloride species comprises chloride ions.

16. The method of claim 15 wherein the chloride ions are derived from a cadmium chloride species.

17. The method of claim 13 further comprising subjecting the copper-poor copper indium disulfide material to a thermal treatment process ranging in temperature from about 100 Degrees Celsius to about 500 Degrees Celsius.

18. The method of claim 13 further comprising introducing an indium species in the window layer to cause formation of an n⁺-type semiconductor characteristic.

19. A method for forming a thin film photovoltaic device, the method comprising:

providing a substrate comprising a surface region;

forming a first electrode layer overlying the surface region;

forming a chalcopyrite material overlying the electrode layer, the chalcopyrite material comprising a copper-poor copper indium disulfide region;

compensating the copper-poor copper indium disulfide region using a chloride species to change its characteristic from an n-type to a p-type;

forming a window layer overlying the chalcopyrite material; and

forming a second electrode layer overlying the window layer.