Patent US4431476A successfully refreshed from Google Patents.
US4431476A
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Method for manufacturing gallium phosphide single crystals
Assignee: Toshiba Corp
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Filing: 1982-01-04
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Granted: 1984-02-14
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Expires: 2002-01-04
Abstract
Abstract A gallium phosphide single crystal is prepared from a polycrystalline gallium phosphide powder as a starting raw material which is obtained by hydrogen reduction of gallium phosphate and which contains residual phosphate radicals in an amount of 0.03 to 0.5% by weight. The gallium phosphide powder is compressed to prepare a green compact which is then melted to provide a gallium phosphide liquid. The gallium phosphide liquid is brought into contact with a seed crystal and is pulled.
Inventors
- 👤 Masayuki Watanabe
- 👤 Jisaburo Ushizawa
- 👤 Tsuguo Fukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:41
CPC Classifications
C; C01; C01B; C01B25/00; C01B25/08; C01B25/082; C01B25/087; C30; C30B; C30B27/00; C30B27/02; C30B29/00; C30B29/10; C30B29/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
121 words
A method for manufacturing gallium phosphide single crystals comprising the steps of: compressing a polycrystalline gallium phosphide powder into a green compact, said green compact having a bulk density of not less than about 2.0 g/cc, the polycrystalline gallium phosphide powder being prepared by hydrogen reduction of gallium phosphate and containing residual phosphate radicals in an amount of 0.03 to 0.5% by weight; placing the green compact in a crucible and placing an encapsulating agent thereover; heating the green compact in a crucible and the encapsulating agent placed in the crucible to provide a gallium phosphide liquid and an encapsulating agent liquid covering thereover; and bringing a seed crystal into contact with the gallium phosphide liquid and pulling the seed crystal.
Claim 2
Independent Claim
121 words
A method for manufacturing gallium phosphide single crystals comprising the steps of: compressing a polycrystalline gallium phosphide powder into a green compact, said green compact having a bulk density of not less than about 2.0 g/cc, the polycrystalline gallium phosphide powder being prepared by hydrogen reduction of gallium phosphate and containing residual phosphate radicals in an amount of 0.03 to 0.5% by weight; placing the green compact in a crucible and placing an encapsulating agent thereover; heating the green compact in a crucible and the encapsulating agent placed in the crucible to provide a gallium phosphide liquid and an encapsulating agent liquid covering thereover; and bringing a seed crystal into contact with the gallium phosphide liquid and pulling the seed crystal.
Claim 3
Dependent Claim
26 words
A method according to claim 1, wherein the hydrogen reduction is performed in at least two stages, and a reaction product is agitated after each stage.
Claim 4
Dependent Claim
20 words
A method according to claim 1, wherein the green compact has a bulk density of about 2.0 to 3.0 g/cc.
Claim 5
Dependent Claim
25 words
A method according to claim 1, wherein the gallium phosphide powder contains the residual phosphate radicals in an amount of 0.05 to 0.1% by weight.
Claim 6
Dependent Claim
13 words
A method according to claim 1, wherein the encapsulating agent is boron oxide.
Claim 7
Dependent Claim
15 words
A method according to claim 1, wherein the seed crystal is pulled while being rotated.
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) | 1987-02-13 | 1987-08-15 | 1988-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-13 | 1991-08-15 | 1992-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-13 | 1995-08-15 | 1996-02-14 | $7700.00 | Window Closed / Lapsed |