US4197141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for passivating imperfections in semiconductor materials
Assignee: Massachusetts Institute of Technology
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Filing: 1978-01-31
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Granted: 1980-04-08
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Expires: 1998-01-31
Abstract
Abstract A method of passivating imperfections, such as grain boundaries and/or dislocations, in semiconductor materials is disclosed which comprises selectively passing electrical current along the imperfections by employing the semiconductor material as an electrode in an electrolytic cell.
Inventors
- 👤 Carl O. Bozler
- 👤 John C. C. Fan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:43
CPC Classifications
H; H10; H10P; H10P95/00; H10F; H10F71/00; H10F71/129; H10F77/00; H10F77/10; H10F77/16; H10F77/162; H10F77/164; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02P; Y02P70/00; Y02P70/50; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24851; Y10T428/24868
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
75 words
A method for passivating imperfections in a semiconductor material, comprising: a. employing said semiconductor material as an anode or cathode in an electrolytic cell; b. applying a voltage across said cell which is sufficient to establish selective current flow along said imperfections; and, c. maintaining selective current flow along said imperfections until (1) the desired passivation is achieved or (2) sufficient material has been deposited or etched to provide the desired passivation upon subsequent treatment.
Claim 2
Independent Claim
75 words
A method for passivating imperfections in a semiconductor material, comprising: a. employing said semiconductor material as an anode or cathode in an electrolytic cell; b. applying a voltage across said cell which is sufficient to establish selective current flow along said imperfections; and, c. maintaining selective current flow along said imperfections until (1) the desired passivation is achieved or (2) sufficient material has been deposited or etched to provide the desired passivation upon subsequent treatment.
Claim 3
Dependent Claim
17 words
A method of claim 1 wherein said semiconductor material comprises a polycrystalline semiconductor material containing grain boundaries.
Claim 4
Dependent Claim
18 words
A method of claim 2 wherein the voltage applied across said cell is below the reverse breakdown voltage.
Claim 5
Dependent Claim
31 words
A method of claim 3 wherein passivation is achieved by the electrodeposition of electrically insulating caps at the intersection of said grain boundaries with the surface of said polycrystalline semiconductor material.
Claim 6
Dependent Claim
29 words
A method of claim 3 wherein passivation is achieved by etching the semiconductor material at the intersection of said grain boundaries with the surface of said polycrystalline semiconductor material.
Claim 7
Dependent Claim
35 words
A method of claim 3 wherein passivation is achieved by electrodepositing an oxidizable material at the intersections of said grain boundaries with the surface of said polycrystalline semiconductor material and subsequently oxidizing said oxidizable material.
Claim 8
Dependent Claim
12 words
A method of claim 6 wherein said oxidizable material comprises a metal.
Claim 9
Dependent Claim
16 words
A method of claim 7 wherein said metal is selected from aluminum, copper, nickel, and chromium.
Claim 10
Dependent Claim
12 words
A passivated polycrystalline semiconductor material produced by the process of claim 2.
Claim 11
Dependent Claim
19 words
A passivated polycrystalline semiconductor material of claim 9 including a transparent conductive film to lower the lateral resistance thereof.
Claim 12
Dependent Claim
17 words
A photovoltaic cell employing a passivated polycrystalline semiconductor material produced according to the process of claim 2.
Claim 13
Dependent Claim
18 words
A photovoltaic cell of claim 11 including an overlying transparent conductive film to lower the lateral resistance thereof.
Claim 14
Dependent Claim
26 words
A method of claim 1 including the additional step of applying a transparent conductive film to said passivated semiconductor material to lower the lateral resistance thereof.
Claim 15
Dependent Claim
13 words
A method of claim 13 wherein said semiconductor material comprises polycrystalline semiconductor material.
Claim 16
Dependent Claim
13 words
A method of claim 14 wherein said polycrystalline semiconductor material comprises gallium arsenide.
Claim 17
Dependent Claim
18 words
A method of claim 15 wherein said transparent conductive film comprises antimony-doped tin oxide or tin-doped indium oxide.
Claim 18
Dependent Claim
19 words
A method of claim 16 wherein said transparent conductive film has a thickness of less than about one micron.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-04-08 | 1983-10-08 | 1984-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-08 | 1987-10-08 | 1988-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-08 | 1991-10-08 | 1992-04-08 | $7700.00 | Window Closed / Lapsed |