Method of producing photovoltaic element

• US 6,221,685 B1
• Filed: 12/02/1998
• Issued: 04/24/2001
• Est. Priority Date: 12/03/1997
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Murakami, Tsutomu, Ichinose, Hirofumi, Ueno, Yukie
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Le, Dung A
• Application Number:
  US09/203,361
• Time in Patent Office: 874 Days
• Field of Search: 438/80, 438/73, 438/48, 438/74, 438/79, 438/81, 204/157.15, 204/140
• US Class Current: 438/48
• CPC Class Codes: H01L 21/67075 for wet etching
• CPC Class Codes: H01L 21/67086 with the semiconductor substrates being dipped in baths or vessels

Abstract

The present invention provides a method of producing a photovoltaic element, which comprises a step of immersing a photovoltaic element having at least a first electrode layer, a semiconductor layer and a second electrode layer formed on a substrate into an electrolytic solution, and removing a short circuit current path caused by a defect in the photovoltaic element under the effect of an electric field, wherein the amount of a first ingredient and the amount of a second ingredient contained in the electrolytic solution are adjusted to control the concentration of hydrogen ions in the electrolytic solution, wherein the constituent substance of the second electrode layer is electrically dissolved by the first ingredient, and thereby it also provides a method of producing photovoltaic elements which is capable of reducing a leakage current caused by defect portions such as pin-holes existing in the photovoltaic elements with a large area to obtain photovoltaic elements with excellent photovoltage generation characteristics under a low illuminance.

Claims

1. A method of producing a photovoltaic element comprising the steps of:

immersing a photovoltaic element having at least a first electrode layer, a semiconductor layer and a second electrode layer formed on a substrate into an electrolytic solution, and

removing a short circuit current path caused by a defect in the photovoltaic element under an effect of an electric field,

wherein an amount of a first ingredient and an amount of a second ingredient in the electrolytic solution is adjusted to control a concentration of hydrogen ions in the electrolytic solution,

wherein a constituent substance of the second electrode layer is electrically dissolved by the first ingredient, and

wherein the first ingredient is an acid solution and the second ingredient is a basic solution.

2. The method of producing a photovoltaic element according to claim 1, wherein the first ingredient includes ions for dissolving the constituent substance of the second electrode layer into the electrolytic solution.

3. The method of producing a photovoltaic element according to claim 1, wherein the concentration of hydrogen ions contained in the electrolytic solution is 1.0×

10<sup>−

3.0</sup> to 1.0×

10<sup>−

1.0</sup> mol/l.

4. The method of producing a photovoltaic element according to claim 1, wherein the electric conductivity of the electrolytic solution is 10 to 100 mS/cm.

5. The method of producing a photovoltaic element according to claim 1, wherein the first ingredient is an acid solution containing at least one selected from the group consisting of sulfate acid, nitric acid, acetic acid, oxalic acid, phosphoric acid, selenic acid and salts of these acids.

6. The method of producing a photovoltaic element according to claim 1, wherein the second ingredient is a basic solution containing at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, aluminum hydroxide, magnesium hydroxide, and ammonia.

7. The method of producing a photovoltaic element according to claim 1, wherein the electric field is an electric field generated by applying a bias to the photovoltaic element.

8. The method of producing a photovoltaic element according to claim 1, wherein the electric field is an electric field generated by a photovoltage generated in the photovoltaic element by irradiating the photovoltaic element with light.

9. The method of producing a photovoltaic element according to claim 7, wherein the bias is applied in a forward direction to the photovoltaic element.

10. The method of producing a photovoltaic element according to claim 1, wherein the substrate is an electroconductive substrate.

11. The method of producing a photovoltaic element according to claim 1, wherein the first electrode layer comprises a plurality of layers including at least one metal layer.

12. The method of producing a photovoltaic element according to claim 1, wherein the semiconductor layer comprises an amorphous semiconductor.

13. The method of producing a photovoltaic element according to claim 1, wherein the second electrode layer comprises a metal oxide.