US3898353A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self aligned drain and gate field effect transistor
Assignee: United States Department of the Army
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Filing: 1974-10-03
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Granted: 1975-08-05
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Expires: 1994-10-03
Abstract
Abstract A method for manufacturing a field effect transistor device utilizing the intentional buildup of material on the source region of the device to mask the gate region of the device and obtain an edge on the drain region which closely follows the contour of the edge on the source region thus permitting a narrow, constant width gate region and more uniform capacitance and current flow between the source and drain regions. The material buildup on the source region of the device is a film of metal which is evaporated on a semiconductor wafer so as to define a pattern with one straight edge.
Inventors
- 👤 Louis Sebastian Napoli
- 👤 Walter Francis Reichert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:42
CPC Classifications
H; H10; H10D; H10D99/00; H10D30/00; H10D30/80; H10D30/87; H10P; H10P95/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
167 words
THE METHOD OF MAKING A FIELD EFFECT TRANSISTOR BY A. PROVIDING A CONDUCTIVE METAL MESA WITH AT LEAST ONE STRAIGHT EDGE ON ONE FLAT SURFACE OF A SEMICONDUCTOR WAFER, B. SUPPORTING THE WAFER ADJACENT TO AN EVAPORATION SOURCE WITH ITS FLAT SURFACE TILTED RELATIVE TO THE SOURCE AND WITH ONE STRAIGHT EDGE ON THE FAR SIDE OF THE MESA RELATIVE TO THE EVAPORATION SOURCE SO THAT THE SEMICONUCTOR REGION IMMEDIATELY ADJACENT TO THE ONE STRAIGHT EDGE IS SHADOWED BY THE STRAIGHT EDGE RELATIVE TO THE EVAPORATION SOURCE, C. EVAPORATING A FILM OF CONDUCTIVE METAL ON THE WAFER WHEREBY THERE IS A FILM FREE GAP ALONGSIDE THE STRAIGHT EDGE, D. STOPPING THE EVAPORATION AND ETCHING THE SEMICONDUCTOR SURFACE IN THE GAP SO THAT THE SEMICONDUCTOR IN THE GAP IS THEN RECESSED, E. POSITIONED THE WAFER SO THAT ITS SURFACE IS APPROXIMATELY NORMAL TO THE SOURCE OF EVAPORATION AND EVAPORATING A METAL FILM ONTO THE WAFER, AND TERMINATING THE EVAPORATION BEFORE THERE IS A SHORT CIRCUIT ACROSS THE GAP.
Claim 2
Independent Claim
167 words
THE METHOD OF MAKING A FIELD EFFECT TRANSISTOR BY A. PROVIDING A CONDUCTIVE METAL MESA WITH AT LEAST ONE STRAIGHT EDGE ON ONE FLAT SURFACE OF A SEMICONDUCTOR WAFER, B. SUPPORTING THE WAFER ADJACENT TO AN EVAPORATION SOURCE WITH ITS FLAT SURFACE TILTED RELATIVE TO THE SOURCE AND WITH ONE STRAIGHT EDGE ON THE FAR SIDE OF THE MESA RELATIVE TO THE EVAPORATION SOURCE SO THAT THE SEMICONUCTOR REGION IMMEDIATELY ADJACENT TO THE ONE STRAIGHT EDGE IS SHADOWED BY THE STRAIGHT EDGE RELATIVE TO THE EVAPORATION SOURCE, C. EVAPORATING A FILM OF CONDUCTIVE METAL ON THE WAFER WHEREBY THERE IS A FILM FREE GAP ALONGSIDE THE STRAIGHT EDGE, D. STOPPING THE EVAPORATION AND ETCHING THE SEMICONDUCTOR SURFACE IN THE GAP SO THAT THE SEMICONDUCTOR IN THE GAP IS THEN RECESSED, E. POSITIONED THE WAFER SO THAT ITS SURFACE IS APPROXIMATELY NORMAL TO THE SOURCE OF EVAPORATION AND EVAPORATING A METAL FILM ONTO THE WAFER, AND TERMINATING THE EVAPORATION BEFORE THERE IS A SHORT CIRCUIT ACROSS THE GAP.
References Cited (Backward Citations)
US3837907A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |