Processing method for cleaning sulfur entities of contact regions

• US 8,642,138 B2
• Filed: 06/01/2009
• Issued: 02/04/2014
• Est. Priority Date: 06/11/2008
• Status: Expired due to Fees

• Current Assignee: Stion Corporation
• Original Assignee: Stion Corporation
• Inventors: Lee, Howard W. H.
• Primary Examiner(s): Cleveland, Michael
• Assistant Examiner(s): HORNING, JOEL G
• Application Number:
  US12/476,174
• Publication Number:
  US 20110020564A1
• Time in Patent Office: 1,709 Days
• Field of Search: None
• US Class Current: 427/554
• CPC Class Codes: H01L 31/022425 for solar cells
• 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 and forming a first electrode layer overlying the surface region of the transparent substrate. The first electrode layer has an electrode surface region. In a specific embodiment, the method includes masking one or more portions of the electrode surface region using a masking layer to form an exposed region and a blocked region. The method includes forming an absorber layer comprising a sulfur entity overlying the exposed region and removing the mask layer. In a specific embodiment, the method causing formation of a plurality of metal disulfide species overlying the blocked region. In a specific embodiment, the metal disulfide species has a semiconductor characteristic. The method includes subjecting the plurality of metal disulfide species to electromagnetic radiation from a laser beam to substantially remove the metal disulfide species. The method includes exposing the blocked region free and clear from the metal disulfide.

Claims

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

providing a transparent substrate having a surface;

forming a first electrode layer over the surface, the first electrode layer having an electrode surface region;

masking the electrode surface region using a masking layer to define an exposed region and a blocked region;

forming an absorber layer, including a sulfur entity, over the exposed region;

removing the masking layer;

exposing a metal disulfide species having a semiconductor characteristic over the blocked region; and

subjecting the metal disulfide species to electromagnetic radiation from a laser to substantially remove the metal disulfide species from the previously blocked region.

2. The method of claim 1 further comprising forming a window layer over the absorber layer.

3. The method of claim 2 further comprising forming a transparent conductive oxide overlying a portion of the window layer.

4. The method of claim 1 wherein the step of forming the absorber layer comprises:

forming a copper layer over the exposed region and an indium layer over the copper layer to thereby form a multi-layered structure;

subjecting the multi-layered structure to heat in an environment containing sulfur to thereby form copper indium disulfide having an atomic ratio of copper to indium between about 1.35 to 1 to about 1.60 to 1.

5. The method of claim 4 wherein the step of subjecting the multi-layered structure to heat also forms a surface layer of copper sulfide on the copper indium disulfide.

6. The method of claim 5 further comprising a step of removing the surface layer of copper sulfide.

7. The method of claim 6 wherein the step of removing the surface layer of copper sulfide comprises using potassium cyanide to selectively remove the copper sulfide.

8. The method of claim 1 wherein the electromagnetic radiation is pulsed.

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

providing a transparent substrate having a surface;

forming a first electrode layer having an electrode surface region over the surface of the transparent substrate;

masking the electrode surface region with a masking layer to define an exposed region and a blocked region;

forming an absorber layer including sulfur over the exposed region;

removing the mask layer;

exposing metal disulfide having a semiconductor characteristic over the blocked region; and

mechanically removing the metal disulfide from the previously blocked region.

10. The method of claim 9 wherein the step of forming the absorber layer comprises:

forming a copper layer over the exposed region and an indium layer over the copper layer to form a multi-layered structure; and

heating the multi-layered structure in an environment containing sulfur to thereby form a copper indium disulfide having an atomic ratio of copper to indium ranging from about 1.35 to 1 to about 1.60 to 1.

11. The method of claim 10 wherein the step of heating also forms a copper sulfide surface region on the copper indium disulfide.

12. The method of claim 11 further comprising using a potassium cyanide solution to remove the copper sulfide.