Patent US4077818A successfully refreshed from Google Patents.
US4077818A
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Process for utilizing low-cost graphite substrates for polycrystalline solar cells
Assignee: National Aeronautics and Space Administration
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Filing: 1976-06-04
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Granted: 1978-03-07
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Expires: 1996-06-04
Abstract
Abstract Low-cost polycrystalline silicon solar cells supported on substrates are prepared by depositing successive layers of polycrystalline silicon containing appropriate dopants over supporting substrates of a member selected from the group consisting of metallurgical-grade polycrystalline silicon, graphite and steel coated with a diffusion barrier of silica, borosilicate, phosphosilicate, or mixtures thereof such that p-n junction devices are formed which effectively convert solar energy to electrical energy. To improve the conversion efficiency of the polycrystalline silicon solar cells, the crystallite size in the silicon is substantially increased by melting and solidifying a base layer of polycrystalline silicon before depositing the layers which form the p-n junction.
Inventors
- 👤 Ting L. Chu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:44
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/22; C23C16/24; H; H10; H10F; H10F10/00; H10F10/10; H10F10/14; H10F71/00; H10F71/128; H10F77/00; H10F77/10; H10F77/16; H10F77/162; H10F77/164; H10F77/1642; H10F77/169; H10F77/1692; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/546; Y02E10/547; Y02P; Y02P70/00; Y02P70/50; Y10; Y10S; Y10S117/00; Y10S117/913; Y10S148/00; Y10S148/12; Y10S148/122; Y10S148/15
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
67 words
A method of fabricating polycrystalline silicon solar cells, which comprises: providing a roughened graphite substrate; depositing a low resistivity polycrystalline silicon layer on the roughened graphite; recrystallizing the polycrystalline silicon layer by melting and solidification; and depositing successive layers of polycrystalline silicon containing appropriate dopants on said low resistivity polycrystalline silicon layer such that p-n junction devices are formed which effectively convert solar energy to electrical energy.
Claim 2
Independent Claim
67 words
A method of fabricating polycrystalline silicon solar cells, which comprises: providing a roughened graphite substrate; depositing a low resistivity polycrystalline silicon layer on the roughened graphite; recrystallizing the polycrystalline silicon layer by melting and solidification; and depositing successive layers of polycrystalline silicon containing appropriate dopants on said low resistivity polycrystalline silicon layer such that p-n junction devices are formed which effectively convert solar energy to electrical energy.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein said low resistivity polycrystalline silicon layer is deposited by the thermal reduction of trichlorosilane with hydrogen.
Claim 4
Dependent Claim
11 words
The method of claim 2 wherein said recrystallizing employs zone melting.
Claim 5
Dependent Claim
11 words
The method of claim 3 wherein said recrystallizing employs unidirectional solidification.
Claim 6
Dependent Claim
31 words
The method of claim 3 wherein said zone melting employs rf coil heating and pulling of the silicon-graphite device to allow the molten zone to traverse the length of the device.
Claim 7
Dependent Claim
31 words
The method of claim 4 wherein said unidirectional solidification employs rf coil heating and adjusting the rf coil spacing so that there is a unidirectional temperature gradient along the silicon-graphite device.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein said graphite substrate is roughened by sandblasting.
Claim 9
Independent Claim
60 words
A method of fabricating polycrystalline silicon solar cells, which comprises: providing a graphite substrate; melting purified metallurgical grade silicon on the graphite; recrystallizing the device formed by unidirectional solidification; and depositing successive layers of polycrystalline silicon containing appropriate dopants on said purified metallurgical grade silicon such that p-n junction devices are formed which effectively convert solar energy to electrical energy.
Claim 10
Independent Claim
60 words
A method of fabricating polycrystalline silicon solar cells, which comprises: providing a graphite substrate; melting purified metallurgical grade silicon on the graphite; recrystallizing the device formed by unidirectional solidification; and depositing successive layers of polycrystalline silicon containing appropriate dopants on said purified metallurgical grade silicon such that p-n junction devices are formed which effectively convert solar energy to electrical energy.
Claim 11
Dependent Claim
15 words
The method of claim 8 wherein said purified metallurgical grade silicon is purified with chlorine.
Claim 12
Dependent Claim
31 words
The method of claim 8 wherein said unidirectional solidification employs rf coil heating and adjusting the rf coil spacing so that there is a unidirectional temperature gradient along the silicon-graphite device.
References Cited (Backward Citations)
US2537255A
Cited
US2840489A
Cited
US2992903A
Cited
US3078328A
Cited
US3335038A
Cited
US3511702A
Cited
US3925577A
Cited
US3900943A
Cited
DE2438588A1
Cited
US3969163A
Cited
US4003770A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-06 | 1981-09-05 | 1982-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-06 | 1985-09-05 | 1986-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-06 | 1989-09-05 | 1990-03-07 | $7700.00 | Window Closed / Lapsed |