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US4251289A
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Gradient doping in amorphous silicon
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1979-12-28
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Granted: 1981-02-17
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Expires: 1999-12-28
Abstract
Abstract An amorphous silicon semiconductor having a gradient doping profile is produced by thermo-electrically diffusing an ionizable deposit material such as antimony or aluminum, for example, into the amorphous silicon layer. Embodied in a photovoltaic device, the gradient doping profile increases the width of the depletion or barrier region and concurrently ensures an ohmic contact between amorphous silicon and current carrying electrodes.
Inventors
- 👤 Theodore D. Moustakas
- 👤 Robert A. Friedman
- 👤 Christopher R. Wronski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:40
CPC Classifications
H; H10; H10F; H10F71/00; H10F71/10; H10F71/103; H10F10/00; H10F10/10; H10F10/18; H10F77/00; H10F77/10; H10F77/16; H10F77/162; H10F77/166; H10F77/1662; H10P; H10P14/00; H10P14/20; H10P14/22; H10P14/32; H10P14/3202; H10P14/3241; H10P14/34; H10P14/3402; H10P14/3404; H10P14/3411; H10P14/3438; H10P14/3441; H10P14/3451; H10P14/3452; H10P14/3454; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/548; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
92 words
A method for producing a gradient doping profile in amorphous silicon comprising: (a) providing a substrate (b) coating said substrate with a layer of dopant material selected from the group consisting of antimony, phosphorous, aluminum, lithium, arsenic or a mixture thereof; (c) RF sputter depositing a layer of photoconductive amorphous silicon while concurrently heating and applying a D.C. positive bias voltage to said dopant layer, where during said deposition the dopant material diffuses into the amorphous silicon layer under the combined driving forces of the applied bias voltage and the elevated temperature.
Claim 2
Independent Claim
92 words
A method for producing a gradient doping profile in amorphous silicon comprising: (a) providing a substrate (b) coating said substrate with a layer of dopant material selected from the group consisting of antimony, phosphorous, aluminum, lithium, arsenic or a mixture thereof; (c) RF sputter depositing a layer of photoconductive amorphous silicon while concurrently heating and applying a D.C. positive bias voltage to said dopant layer, where during said deposition the dopant material diffuses into the amorphous silicon layer under the combined driving forces of the applied bias voltage and the elevated temperature.
Claim 3
Independent Claim
92 words
A method for producing an improved semiconductor device having a gradient doped semiconductor region, said method comprising: (a) providing a substrate having at least one surface comprising an electrical conductor; (b) coating said surface with a layer of dopant material selected from the group consisting of antimony, phosphorous, aluminum, lithium, arsenic or a mixture thereof; (c) RF sputter depositing a layer of photoconductive amorphous silicon on said coated surface while concurrently heating and applying a D.C. positive bias voltage to said dopant layer; (d) forming a junction on said amorphous silicon layer.
Claim 4
Independent Claim
92 words
A method for producing an improved semiconductor device having a gradient doped semiconductor region, said method comprising: (a) providing a substrate having at least one surface comprising an electrical conductor; (b) coating said surface with a layer of dopant material selected from the group consisting of antimony, phosphorous, aluminum, lithium, arsenic or a mixture thereof; (c) RF sputter depositing a layer of photoconductive amorphous silicon on said coated surface while concurrently heating and applying a D.C. positive bias voltage to said dopant layer; (d) forming a junction on said amorphous silicon layer.
Claim 5
Dependent Claim
32 words
The method of claim 1 or 2 wherein said bias voltage ranges from about 30 volts to about 100 volts and said temperatures range from about 200° C. to about 300° C.
Claim 6
Dependent Claim
33 words
The method of claim 1 or 2 wherein said bias voltage ranges from about 50 volts to about 100 volts and said temperature is maintained between about 250° C. and about 300° C.
Claim 7
Dependent Claim
19 words
The method of claim 1 or 2 wherein said dopant layer comprises a 100 Angstrom thick layer of antimony.
Claim 8
Dependent Claim
21 words
The method of claim 2 wherein said amorphous silicon layer is between about 1 micron and about 3 microns in thickness.
Claim 9
Dependent Claim
29 words
The method of claim 2 wherein said semiconductor junction comprises a Schottky junction formed by depositing a layer of metal having a work function exceeding about 4.5 electron volts.
Claim 10
Dependent Claim
16 words
A photovoltaic device produced by the method of claim 7 and wherein said metal comprises palladium.
Claim 11
Independent Claim
58 words
A method for forming an ohmic contact to intrinsic photoconductive amorphous silicon which comprises diffusing a layer of antimony into the surface of said amorphous silicon to be contacted by means of heating and applying a D.C. bias voltage to said antimony layer during the formation of the amorphous silicon layer on said antimony layer by RF sputtering.
Claim 12
Independent Claim
58 words
A method for forming an ohmic contact to intrinsic photoconductive amorphous silicon which comprises diffusing a layer of antimony into the surface of said amorphous silicon to be contacted by means of heating and applying a D.C. bias voltage to said antimony layer during the formation of the amorphous silicon layer on said antimony layer by RF sputtering.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-17 | 1984-08-18 | 1985-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-17 | 1988-08-18 | 1989-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-17 | 1992-08-18 | 1993-02-17 | $7700.00 | Window Closed / Lapsed |