US3829382A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Doping control for semiconductor materials
Assignee: SunEdison Inc
•
Filing: 1972-05-15
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Granted: 1974-08-13
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Expires: 1992-05-15
Abstract
Abstract THE IMPURITY CONCENTRATION OF A SEMICONDUCTOR MATERIAL BEING PROCESSED, SUCH AS BY ZONE REFINING, IS PRECISION CONTROLLED BY FLOWING A DOPANT GAS TO A TIME-CONTROLLED PROPORTIONING DEVICE WHICH FEEDS A PRESELECTED FRACTION OF THE DOPANT TO THE SEMICONDUCTOR MATERIAL. THE DOPANT GAS FLOWS AT A CONSTANT FLOW RATE AND CONSTANT PRESSURE TO THE PROPORTIONING DEVICE THEREBY ELIMINATING MEMORY OR STORAGE EFFECTS IN THE DOPING SYSTEM AND IMPROVING THE DOPING CONTROL OF THE PROCESSED MATERIAL.
Inventors
- 👤 W Tucker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:13
CPC Classifications
C; C30; C30B; C30B13/00; C30B13/08; C30B13/10; C30B13/12; Y; Y10; Y10S; Y10S438/00; Y10S438/935
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |