US3676229A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making transistors including base sheet resistivity determining step
Assignee: RCA Corp
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Filing: 1971-01-26
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Granted: 1972-07-11
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Expires: 1991-01-26
Abstract
Abstract A SEMICONDUCTOR WAFER HAS A UNIFORMLY THICK COLLECTOR LAYER THEREIN WITH A UNIFORMLY THICK BASE LAYER ADJACENT THE COLLECTOR LAYER. A PLURALITY OF EMITTER REGIONS ARE DIFFUSED INTO THE BASE LAYER FROM THE SURFACE. DURING EMITTER DIFFUSION, AN ANNULAR REGION OF THE SAME CONDUCTIVITY AS THE EMITTER REGIONS IS ALSO DIFFUSED INTO THE BASE LAYER TO SURROUND A PORTION OF THE BASE LAYER AT THE SURFACE. THE SHEET RESISTIVITY OF THE BASE LAYER BETWEEN THE ANNULAR REGION AND THE COLLECTOR LAYER IS DETERMINED, AND IF BELOW A DESIRED MINMUM, THE EMITTER AND ANNULAR REGIONS ARE FURTHER DIFFUSED.
Inventors
- 👤 Willem Gerard Einthoven
- 👤 Evelyn Speter Jetter
- 👤 Carl Franklin Wheatley Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:56
CPC Classifications
H; H10; H10P; H10P74/00; H10P74/20; H10P74/207; G; G01; G01R; G01R31/00; G01R31/26; G01R31/2607; G01R31/2637; G01R31/2644; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/177; H10P74/23; Y; Y10; Y10S; Y10S148/00; Y10S148/085; Y10S148/162
Claims Analysis
Total Claims: 0
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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) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |