US3566519A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making field effect transistor device
Assignee: Sprague Electric Co
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Filing: 1968-04-01
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Granted: 1971-03-02
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Expires: 1988-04-01
Abstract
Abstract A HIGH PURITY COATING OF DIELECTRIC MATERIAL IS FIRST FORMED OVER A MAJOR SURFACE OF SEMICONDUCTIVE BODY OF ONE CONDUCTIVITY TYPE. THE COATING IS THEN PURIFIED BY REMOVAL OF A THIN LAYER OF ITS OUTER SURFACE, AND SPACED APART REGIONS OF THE OTHER CONDUCTIVITY TYPE ARE DIFFUSED WITHIN THE BODY ADJACENT ITS MAJOR SURFACE. THE COATING IS AGAIN PURIFIED BY REMOVAL OF A THIN OUTER LAYER, AND THE THICKNESS OF COATING IS REDUCED IN AN AREA OVERLYING THE CHANNEL FORMED BY THE SEPARATION BETWEEN REGIONS SO AS TO PROVIDE A GATE INSULATION HIGH PURITY WITHOUT EXPOSURE OF JUNCTIONS.
Inventors
- 👤 Jerome F Lapham Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:23
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0215; H10D99/00; H10P; H10P14/00; H10P14/60; H10P32/00; Y; Y10; Y10S; Y10S148/00; Y10S148/017; Y10S148/043; Y10S148/053; Y10S148/06; Y10S148/106
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |