US3671330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of acceptor impurities from high purity germanium
Assignee: General Electric Co
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Filing: 1970-10-21
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Granted: 1972-06-20
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Expires: 1990-10-21
Abstract
Abstract ULTRA-PURE GERMANIUM IS PREPARED FREE OF ACCEPTOR IMPURITIES BY MELTING ZONE REFINED, OR COMPARABLE PURITY, GERMANIUM INA QUARTZ CRUCIBLE AND GROWING SINGLE CRYSTALS FROM THE MELT BY SEED CRYSTAL WITHDRAWAL INGOT GROWTH. THE PROCESS IS REPEATED UNTIL THE DESIRED PURITY IS OBTAINED. PRIOR TO RE-USE OF PREVIOUSLY USED CRUCIBLES, CRUCIBLES ARE ETCHED TO REMOVE ACCEPTOR-QUARTZ REACTION PRODUCT FROM THE SURFACE THEREOF.
Inventors
- 👤 Robert N Hall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:05
CPC Classifications
C; C30; C30B; C30B15/00; C30B15/10; C30B13/00; C30B13/14; C30B29/00; C30B29/02; C30B29/08; Y; Y10; Y10S; Y10S117/00; Y10S117/90; Y10S148/00; Y10S148/017; Y10S148/107; Y10S148/13
Claims Analysis
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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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |