US4543171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for eliminating defects in a photodetector
Assignee: RCA Corp
•
Filing: 1984-03-22
•
Granted: 1985-09-24
•
Expires: 2004-03-22
Abstract
Abstract The performance of a photodetector is reduced by the presence of an electrical defect such as a short or a shunt. The invention is a method of improving the performance of this photodetector by preferentially removing a portion of an exposed surface of a detector electrode at the defect site. The preferential etching of the exposed surface is obtained by immersing the photodetector in a chemical etching ambient which has an etching rate for the exposed surface of the electrode which increases with increasing temperature while applying a reverse-bias voltage to the electrodes. The reverse-bias voltage has sufficient magnitude to cause a local increase in temperature of the exposed surface at the defect site.
Inventors
- 👤 Arthur H. Firester
- 👤 Robert V. D'Aiello
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:11
CPC Classifications
H; H10; H10F; H10F71/00; H10F71/135; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02P; Y02P70/00; Y02P70/50; Y10; Y10S; Y10S136/00; Y10S136/29
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
100 words
A method for improving the performance of a photodetector having an electrical defect therein and comprising a pair of electrodes on a semiconductor body, said method comprising the step of immersing said photodetector in a chemical ambient having an etching rate for an exposed surface of at least one of said electrodes which increases with increasing temperature while applying a reverse-bias voltage of sufficient magnitude to said electrodes to cause a local increase in the temperature of said exposed surface at said defect for a sufficient period of time to remove a portion of said exposed electrode at said defect.
Claim 2
Independent Claim
100 words
A method for improving the performance of a photodetector having an electrical defect therein and comprising a pair of electrodes on a semiconductor body, said method comprising the step of immersing said photodetector in a chemical ambient having an etching rate for an exposed surface of at least one of said electrodes which increases with increasing temperature while applying a reverse-bias voltage of sufficient magnitude to said electrodes to cause a local increase in the temperature of said exposed surface at said defect for a sufficient period of time to remove a portion of said exposed electrode at said defect.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said etching ambient is a gas.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein said etching ambient is a liquid.
Claim 5
Dependent Claim
24 words
The method of claim 1 further comprising the step of cooling said chemical etching ambient below 20° C. prior to immersing said photodetector therein.
Claim 6
Dependent Claim
48 words
The method of claim 1 wherein said photodetector comprises a substrate, a first electrode overlying a surface of said substrate, a semiconductor body containing amorphous silicon and having a semiconductor junction therein overlying said first electrode and a second electrode comprising a metallic layer overlying said semiconductor body.
Claim 7
Dependent Claim
22 words
The method of claim 1 wherein the local increase in temperature of said electrode at said defect is at least 20° C.
Claim 8
Dependent Claim
18 words
The method of claim 6 wherein the reverse-bias voltage applied between said electrodes is at least one volt.
Claim 9
Dependent Claim
22 words
The method of claim 7 wherein said reverse-bias voltage applied between said electrodes is less than the breakdown voltage of said photodetector.
Claim 10
Dependent Claim
48 words
The method of claim 1 wherein said exposed electrode comprises a metal layer on the surface of the semiconductor body and a passivation layer overlying the metal layer and wherein the portion of the surface of said exposed electrode removed at the defect site is the passivation layer.
Claim 11
Dependent Claim
29 words
The method of claim 9 further comprising the step of etching the photodetector to remove the metal layer at the defect site after the passivation layer has been removed.
References Cited (Backward Citations)
US4064521A
Cited
US4094733A
Cited
US4166918A
Cited
US4436581A
Cited
US4385971A
Cited
US4464823A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-23 | 1989-03-25 | 1989-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-23 | 1993-03-25 | 1993-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-23 | 1997-03-25 | 1997-09-24 | $7700.00 | Window Closed / Lapsed |