Conversion process for passivating short circuit current paths in semiconductor devices

• US 4,729,970 A
• Filed: 09/15/1986
• Issued: 03/08/1988
• Est. Priority Date: 09/15/1986
• Status: Expired due to Term

• Current Assignee: United Solar Systems Corp.
• Original Assignee: Energy Conversion Devices
• Inventors: Nath, Prem, Vogeli, Craig
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US06/907,425
• Time in Patent Office: 540 Days
• Field of Search: 437/2, 437/4, 437/5, 437/10, 437/12, 437/170, 437/171, 437/181, 225/233, 225/235, 225/923, 225/939, 136/258 AM, 136/290, 204/130, 204/140, 204/15
• US Class Current: 438/4
• CPC Class Codes: H01L 21/28 Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268 etching for patterning the electrodes H01L21/311, H01L21/3213; multistep manufacturing processes for data storage electrodes H01L29/4011
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/208 Particular post-treatment of the devices, e.g. annealing, short-circuit elimination
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 136/29 Testing, calibrating, treating, e.g. aging

Abstract

An electronic device of the type including a thin film body having a superposed electrode has short circuit defects therein passivated by a conversion process in which the electrical resistivity of the electrode material is increased proximate the defect regions. Conversion is accomplished by exposing the electrode material to a conversion reagent and activating the reagent proximate the defect regions. The process may be utilized for a variety of differently configured devices, and may be readily adapted for use in a roll-to-roll device fabrication process.

Claims

1. A method of passivating short circuit defects in an electronic device of the type including a thin film body having a superposed electrode comprised of a layer of transparent, electrically conductive oxide material, said method including the steps of:

providing a conversion reagent in contact with at least those portions of the electrode proximate said defects, said reagent adapted to convert the electrically conductive electrode material to a material of higher electrical resistivity; and

activating said conversion reagent proximate said defects so as to alter the stoichiometry of the transparent conductive oxide material to the higher resistivity form, whereby said defect regions are substantially electrically isolated from the remainder of said electrode.

2. A method as in claim 1, wherein the step of activating the conversion reagent to alter the stoichiometry of the oxide material includes changing the number of oxygen vacancies in said oxide material.

3. A method as in claim 2, wherein the step of changing the number of oxygen vacancies comprises exposing said oxide material to reducing conditions.

4. A method as in claim 2, wherein the step of changing the number of oxygen vacancies comprises exposing said oxide material to oxidizing conditions.

5. A method as in claim 1, wherein the step of activating the conversion reagent includes the further step of passing an electrical current through at least the defect regions of the thin film body and into the superposed electrode so as to activate the conversion reagent proximate thereto.

6. A method as in claim 5, including the further steps of providing a counter-electrode disposed in electrical communication with the conversion reagent and the electrode of the device;

and, providing a source of electrical current in electrical communication with the semiconductor body and the counter-electrode.

7. A method as in claim 1, wherein the step of activating the conversion reagent includes the step of heating the reagent proximate said defects.

8. A method as in claim 1, wherein the step of activating the conversion reagent includes the step of illuminating the conversion reagent proximate said defects.

9. A method of passivating short circuit defects in an electronic device of the type including a thin film body having a superposed electrode comprised of a layer of electrically conductive material, said method including the steps of:

providing a conversion reagent, including therein a Lewis Acid, in contact with at least those portions of the electrode proximate said defects, said reagent adapted to convert the electrically conductive electrode material to a material of higher electrical resistivity; and

activating said conversion reagent proximate said defects so as to facilitate conversion of the electrode material to the higher resistivity form, whereby said defect regions are substantially electrically isolated from the remainder of said electrode.

10. A method of passivating short circuit defects in an electronic device of the type including a thin film body having a superposed electrode comprised of a layer of electrically conductive material, said method including the steps of:

providing a conversion reagent, including therein a salt of an amphoteric element, in contact with at least those portions of the electrode proximate said defects, said reagent adapted to convert the electrically conductive electrode material to a material of higher electrical resistivity; and

activating said conversion reagent proximate said defects so as to facilitate conversion of the electrode material to the higher resistivity form, whereby said defect regions are substantially electrically isolated from the remainder of said electrode.

11. A method as in claim 10, including the further step of selecting said salt from the group consisting essentially of:

AlCl₃, ZnCl₂, SnCl₄, SnCl₂, TiCl₄, and combinations thereof.

12. A method as in claim 10, wherein the step of providing a conversion reagent comprises providing an aqueous conversion reagent.

13. A method as in claim 10, wherein the step of providing a conversion reagent comprises providing a reagent including a non-aqueous solvent therein.

14. A method as in claim 10, wherein the electronic device includes at least one latent defect therein, said method including the further step of:

activating said at least one latent defect so as to convert it to a short circuit defect.

15. A method as in claim 14, wherein the step of activating latent defects includes passing an electrical current through said defects.

16. A method as in claim 14, wherein said latent defects are activated prior to the activation of said conversion reagent.

17. A method as in claim 14, wherein said latent defects are activated concomitant with the activation of said conversion reagent.