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US4889493A
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Method of manufacturing the substrate of GaAs compound semiconductor
Assignee: Furukawa Electric Co Ltd
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Filing: 1988-08-09
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Granted: 1989-12-26
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Expires: 2008-08-09
Abstract
Abstract A method of manufacturing a substrate of a GaAs compound semiconductor is disclosed, which is characterized in that, after a crystal of GaAs compound semiconductor obtained by the liquid encapsulated Czocharalski method is annealed in the form of ingot, gradually cooled to room temperature and cut off in the form of a wafer, a re-heating treatment consisting of heating to a temperature of not lower than 700° C., rapid cooling from the temperature of not lower than 700° C. to a temperature of not higher than 400° C. within 30 minutes and successive cooling to room temperature is given to the wafer, and then mirror polishing is performed.
Inventors
- 👤 Yasuo Otsuki
- 👤 Yoshio Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:42
CPC Classifications
C; C30; C30B; C30B33/00; C30B29/00; C30B29/10; C30B29/40; C30B29/42; Y; Y10; Y10S; Y10S438/00; Y10S438/974
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
90 words
A method of manufacturing a substrate of a GaAs compound semiconductor, comprising annealing an ingot of a crystal of GaAs compound semiconductor obtained by the liquid encapsulated Czochralski method, gradually cooling the annealed ingot to room temperature, cutting off a wafer therefrom, reheating said wafer by heating it to a temperature of not lower than 700° C., rapidly cooling the wafer from the temperature of not lower than 700° C. to a temperature of not higher than 400° C. within 30 minutes and successively cooling the wafer to room temperature.
Claim 2
Independent Claim
90 words
A method of manufacturing a substrate of a GaAs compound semiconductor, comprising annealing an ingot of a crystal of GaAs compound semiconductor obtained by the liquid encapsulated Czochralski method, gradually cooling the annealed ingot to room temperature, cutting off a wafer therefrom, reheating said wafer by heating it to a temperature of not lower than 700° C., rapidly cooling the wafer from the temperature of not lower than 700° C. to a temperature of not higher than 400° C. within 30 minutes and successively cooling the wafer to room temperature.
Claim 3
Dependent Claim
29 words
The method of manufacturing the substrate of GaAs compound semiconductor according to claim 1, wherein the reheating of the wafer is carried out in an atmosphere of nitrogen gas.
Claim 4
Dependent Claim
25 words
The method of manufacturing the substrate of GaAs compound semiconductor according to claim 1, wherein after cooling to room temperature the wafer is mirror polished.
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) | 1992-12-25 | 1993-06-26 | 1993-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-25 | 1997-06-26 | 1997-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-25 | 2001-06-26 | 2001-12-26 | $7700.00 | Window Closed / Lapsed |