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US3660179A
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Gaseous diffusion technique
Assignee: Westinghouse Electric Corp
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Filing: 1970-08-17
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Granted: 1972-05-02
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Expires: 1990-08-17
Abstract
Abstract A counter-flow of an inert, or a predominantly inert, gas is provided in a diffusion furnace to provide means for creating turbulence within the diffusion system thereby improving the uniformity of dopant along the length of the diffusion carrier contained therein.
Inventors
- 👤 Timothy J Desmond
- 👤 Berton P Krumanacker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:57
CPC Classifications
C; C30; C30B; C30B31/00; C30B31/06; C30B31/16; H; H10; H10P; H10P95/00; Y; Y10; Y10S; Y10S118/00; Y10S118/90; Y10S148/00; Y10S148/006; Y10S252/00; Y10S252/95; Y10S252/951; Y10S438/00; Y10S438/935
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
23 words
The process as defined in claim 1 in which said inert gas is one selected from the group consisting of nitrogen and argon.
Claim 2
Dependent Claim
17 words
The process as defined in claim 2 wherein said second gaseous stream further contains, a dopant material.
Claim 3
Dependent Claim
28 words
The process as defined in claim 1 wherein said second gaseous stream has a flow rate of at least twice the flow rate of said first gaseous stream.
Claim 4
Dependent Claim
31 words
The process as defined in claim 1 wherein the first gaseous stream comprises oxygen, nitrogen and a doping gas mixture of dibrane and nitrogen and the second gaseous stream comprises nitrogen.
Claim 5
Dependent Claim
17 words
The process as defined in claim 5 wherein the second gaseous stream further contains oxygen, and diborane.
Claim 6
Dependent Claim
83 words
The process as defined in claim 5 wherein the flow rate of the oxygen is 180 cc./min., the flow rate of nitrogen of the first gaseous stream is 4,300 cc./min., the flow rate of the diborane doping gas mixture is 9 cc./min., the flow rate of nitrogen in the second gaseous stream is no greater than 15 l./min., the furnace has an inside diameter of 60 mm. ID, said predetermined distance is from 3 to 4 inches, and said semiconductor material is silicon.
Claim 7
Dependent Claim
21 words
The process as defined in claim 7 wherein the flow rate of nitrogen in said second gaseous stream is 10.4 l./min.
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) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |