US3756861A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bipolar transistors and method of manufacture
Assignee: AT&T Inc
•
Filing: 1972-03-13
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Granted: 1973-09-04
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Expires: 1992-03-13
Abstract
Abstract A BIPOLAR TRANSISTOR IS FABRICATED BY MEANS OF A TWOSTEP BASE FORMATION AND AN EMITTER FORMED BY CHEMICLA DIFFUSION OR ION IMPLANTATION. ONE PROCESSING STEP IN FORMING THE BASE IS EITHER A DIFFUSION OF ION IMPLANTATION OF IMPURITIES WHICH DETERMINE SHEET RESISTIVITY. THE OTHER PROCESSING STEP IS AN ION IMPLANTATION WHICH DETERMINES DOPING CONCENTRATION UNDER THE EMITTER. THE RESULTING COMPOSITE DOPING PROFILE HAS A MINIUM AND TWO PEAK VALUES. THE EMITTER IS PREFERABLY IMPLANTED AND THEN DIFFUSED TO A DEPTH WHICH LOCATES THE EMITTER-BASE JUNCTION AT OR NEAR THE MINIMUM OF THE BASE PROFILE. D R A W I N G
Inventors
- 👤 R Payne
- 👤 R Scavuzzo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:10
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H10P30/202; H10P30/204; H10P30/21; H10P30/212; H10P30/28; Y; Y10; Y10S; Y10S148/00; Y10S148/04; Y10S148/041; Y10S148/067; Y10S148/085; Y10S148/145; Y10S148/151
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) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |