US4131659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing large-size, self-supporting plates of silicon
Assignee: Wacker Chemie AG
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Filing: 1976-11-19
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Granted: 1978-12-26
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Expires: 1996-11-19
Abstract
Abstract Process for producing large-size, self-supporting plates of silicon deposd from the gaseous phase on a substrate body, which comprises heating a graphite substrate to deposition temperature of silicon, which is deposited on the substrate from a gaseous compound to which a dopant has been added until a layer of about 200 to 650 μm has formed, subsequently melting 40-100% of this layer from the free surface downward, resolidifying the molten silicon by adjustment of a temperature gradient from the substrate body upward, and finally separating the silicon therefrom. The plates so formed are used primarily for making solar cells.
Inventors
- 👤 Bernhard Authier
- 👤 Rudolf Griesshammer
- 👤 Franz Koppl
- 👤 Winfried Lang
- 👤 Erhard Sirtl
- 👤 Heinz-Jorg Rath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:01
CPC Classifications
C; C30; C30B; C30B13/00; C30B13/06; C23; C23C; C23C16/00; C23C16/01; C30B13/005; C30B29/00; C30B29/60; Y; Y10; Y10S; Y10S117/00; Y10S117/914; Y10S117/915; Y10S438/00; Y10S438/907
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
150 words
A process for producing large-size, self-supporting plates of silicon deposited from the gaseous phase on a substrate body, comprising the steps of: heating a graphite substrate to the decomposition temperature of silicon; depositing silicon from a gaseous compound to which a dopant of a first conductivity has been added, upon said substrate, in solid form until a layer of about 200 to 600 μm has formed; subsequently melting 40-100% of said layer from the free surface downward; resolidifying the molten silicon from the substrate body upwardly to the free surface of the molten silicon layer to effect an oriented growth of the resolidifying silicon from the substrate toward the free surface, said resolidifying step being effected by maintaining a vertically directed temperature gradient between the lower surface and the free surface of said molten layer until said molten layer is completely resolidified; and finally separating the silicon from said substrate.
Claim 2
Dependent Claim
150 words
A process for producing large-size, self-supporting plates of silicon deposited from the gaseous phase on a substrate body, comprising the steps of: heating a graphite substrate to the decomposition temperature of silicon; depositing silicon from a gaseous compound to which a dopant of a first conductivity has been added, upon said substrate, in solid form until a layer of about 200 to 600 μm has formed; subsequently melting 40-100% of said layer from the free surface downward; resolidifying the molten silicon from the substrate body upwardly to the free surface of the molten silicon layer to effect an oriented growth of the resolidifying silicon from the substrate toward the free surface, said resolidifying step being effected by maintaining a vertically directed temperature gradient between the lower surface and the free surface of said molten layer until said molten layer is completely resolidified; and finally separating the silicon from said substrate.
Claim 3
Dependent Claim
36 words
The process according to claim 1, wherein an intermediate layer is applied to the substrate body before the silicon is deposited, said intermediate layer remaining adhered to said substrate body following separation of said silicon therefrom.
Claim 4
Dependent Claim
15 words
The process according to claim 2 wherein silicon nitride is applied as said intermediate layer.
Claim 5
Dependent Claim
22 words
The process according to claim 1 wherein the gaseous compound from which silicon is deposited is a mixture of trichlorosilane and hydrogen.
Claim 6
Dependent Claim
21 words
The process according to claim 1 wherein the dopant added to the gaseous compound is one which leads to a p-conduction.
Claim 7
Dependent Claim
20 words
The process according to claim 1 wherein the deposited silicon is melted by a radiation source mounted above the same.
Claim 8
Dependent Claim
22 words
The process according to claim 1 wherein the main energy supply for the melting is delivered by heating up the substrate body.
Claim 9
Dependent Claim
56 words
The process according to claim 1, wherein the resolidified silicon surface is melted once more to a depth of 0.5 to 1.5 μm in the presence of a volatile dopant of an opposite conductivity relative to said first dopant which causes the remelted silicon to become doped in opposite conductivity relative to the adjacent silicon layer.
Claim 10
Dependent Claim
24 words
The process according to claim 1 wherein the substrate body is continuously reintroduced into the process after the silicon layer has been removed therefrom.
Claim 11
Dependent Claim
21 words
The process according to claim 1 wherein the self-supporting silicon layer is cut into plates to be used as solar cells.
References Cited (Backward Citations)
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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) | 1981-12-25 | 1982-06-26 | 1982-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-25 | 1986-06-26 | 1986-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-25 | 1990-06-26 | 1990-12-26 | $7700.00 | Window Closed / Lapsed |