US2992080A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of improving the purity of silicon
Assignee: General Electric Co
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Filing: 1958-07-25
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Granted: 1961-07-11
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Expires: 1978-07-25
Abstract
No abstract record available.
Inventors
- 👤 Carlyle S Herrick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:39
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/02; C01B33/037; C01B33/021; C01B33/027; C01B33/033
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
62 words
A METHOD OF REMOVING SIC FILM ON SILICON WHICH COMPRISES, HEATING THE SILICON TO APPROXIMATELY 100*C. UNDER VACUUM OF APPROXIMATELY 1-20 MICRONS OF MERCURY ABSOLUTE, MAINTAINING THE PRESSURE AND TEMPERATURE FOR A PERIOD IN EXCESS OF 24 HOURS, COOLING THE SILICON TO ROOM TEMPERATURE, AND IMMERSING THE SILICON IN AN ETCHING SOLUTION TO REMOVE A LAYER OF SILICON BENEATH THE COVERING FILM.
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) | 1964-07-10 | 1965-01-09 | 1965-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-07-10 | 1969-01-09 | 1969-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-07-10 | 1973-01-09 | 1973-07-11 | $7700.00 | Window Closed / Lapsed |