US3615930A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing silicon carbide crystals
Assignee: US Philips Corp
•
Filing: 1967-10-25
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Granted: 1971-10-26
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Expires: 1987-10-25
Abstract
Abstract A method of manufacturing silicon carbide crystals with a narrow PN junction in which during growth of such crystals by recrystallization and/or condensation in an inert gas atmosphere in a space bounded by silicon carbide, dopants which can result in different conductivities are successively supplied to the crystallization space. N-type crystals are formed at temperatures between 2,300* and 2,600* C. in presence of a donor. Then the temperature is decreased to 2,000* C. and the space freed of the donor. Aluminum is then supplied to the space and the temperature raised to 200* to 300* C. lower than that at which the first part of the crystals were formed.
Inventors
- 👤 Wilhelmus Franciscu Knippenber
- 👤 Arthur William Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:58
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/01; H10H20/011; H10H20/014; Y; Y10; Y10S; Y10S148/00; Y10S148/148; Y10S252/00; Y10S252/95; Y10S252/951; Y10S438/00; Y10S438/931
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
24 words
A method as set forth in claim 1 wherein the first temperature is approximately 2,550* C., and the second temperature is approximately 2,250* C.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |