Patent US3770521A successfully refreshed from Google Patents.
US3770521A
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US
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Method for diffusing b or p into s: substrates
Assignee: International Business Machines Corp
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Filing: 1971-04-14
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Granted: 1973-11-06
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Expires: 1991-04-14
Abstract
Abstract A method is disclosed whereby a semiconductor silicon substrate wafer is diffused with a P or N type dopant or ''''impurity'''' in an open tube at a temperature of about 1050*C in the presence of at least a 50:1 ratio of water to dopant whereby the surface concentration of impurity is controlled below the solid solubility of the dopant in silicon.
Inventors
- 👤 R Lever
- 👤 P Melzer
- 👤 H Demsky
- 👤 W Dexter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:36
CPC Classifications
H; H10; H10P; H10P95/00; H10P32/00; Y; Y10; Y10S; Y10S438/00; Y10S438/914; Y10S438/92
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
81 words
A method for diffusing a boron or phosphorus conductivity type dopant in a silicon semiconductor substrate comprising a. heating said silicon semiconductor substrate to a temperature between 950*C and 1050*C at atmospheric pressure, and b. separately introducing a 1:50 ratio by weight of a conductivity type dopant selected from the group consisting of boron tribromide and phosphorus oxytrichloride and water in close proximity to said heated substrate for a period between 50 and 130 minutes, and c. cooling to room temperature.
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) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |