Patent US3791884A successfully refreshed from Google Patents.
US3791884A
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Method of producing a pnp silicon transistor
Assignee: Siemens AG
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Filing: 1971-02-19
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Granted: 1974-02-12
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Expires: 1991-02-19
Abstract
Abstract During the production of a pnp silicon transistor, one side of a p-conducting silicon wafer is provided with a base zone through masked diffusion of phosphorus atoms. A subsequent diffusion process increases the phosphorus concentration at the surface of the base zone to 1020 to 1021 phosphorous atoms/cm3. The same phosphorus concentration is produced at the opposite side of the silicon wafer. The emitter is produced in the region of the base zone through a masked diffusion of acceptor atoms. Finally, the phosphorus-doped layer is removed from the reverse or back side of the semiconductor wafer.
Inventors
- 👤 W Muller
- 👤 J Dathe
- 👤 L Grasser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:06
CPC Classifications
H; H10; H10P; H10P95/00; H10P32/00; H10P32/10; H10P32/12; H10P32/17; H10P32/171; H10W; H10W74/00; H10W74/40; H10W74/43; Y; Y10; Y10S; Y10S438/00; Y10S438/928
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
19 words
The method of claim 1 wherein the indiffusion of the phosphorus is effected at a temperature of about 1050*C.
Claim 2
Dependent Claim
31 words
The method of claim 1, wherein following the last diffusion process, contact points are exposed at the base and the emitter zone and are contacted by a vapor deposited aluminum layer.
Claim 3
Dependent Claim
24 words
The method of claim 3, wherein the aluminum layer is locally vapor-deposited upon the contact points of the base and of the emitter zone.
Claim 4
Dependent Claim
46 words
The method of claim 3, wherein the semiconductor surface provided with the exposed contact points of the base and of the emitter zone, is covered by a total area aluminum metallization by vapor deposition, said metallization is then removed locally by the photo resist etching method.
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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |