Patent US4587540A successfully refreshed from Google Patents.
US4587540A
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Vertical MESFET with mesa step defining gate length
Assignee: International Business Machines Corp
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Filing: 1985-01-17
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Granted: 1986-05-06
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Expires: 2005-01-17
Abstract
Abstract The edge of a conformal coating over a mesa is usable to define a shoulder in the vertical dimension of the mesa which in turn is used for positioning. Structures are provided that permit electrodes at precise locations along the length of a mesa. A vertical field effect transistor is set forth with a mesa serving as the channel and the gate electrode positioned at a shoulder formed by the edge dimension of a coating on the sides of the mesa.
Inventors
- 👤 Thomas N. Jackson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:07
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/69; H10P50/691; H10D; H10D62/00; H10D62/10; H10D62/113; H10D62/115; H10D62/116; H10D64/00; H10D64/01; H10D64/011
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
138 words
A semiconductor structure comprising in combination: a monocrystalline semiconductor substrate of one conductivity type having a planar top surface and a mesa extending from said planar top surface; wherein said mesa has a step at a given distance from said planar top surface defining a base of said mesa which has a larger cross sectional area than the portion above the step; an electrode with a thickness equal to said given distance which forms a rectifying contact with said base of said mesa; wherein said electrode is formed on said planar top surface around the periphery of said mesa contiguous with said base of said mesa; and wherein said semiconductor substrate is semi-insulating in that region directly under and contiguous with said electrode; ohmic contacts formed on the top of said mesa and the bottom of said substrate.
Claim 2
Dependent Claim
138 words
A semiconductor structure comprising in combination: a monocrystalline semiconductor substrate of one conductivity type having a planar top surface and a mesa extending from said planar top surface; wherein said mesa has a step at a given distance from said planar top surface defining a base of said mesa which has a larger cross sectional area than the portion above the step; an electrode with a thickness equal to said given distance which forms a rectifying contact with said base of said mesa; wherein said electrode is formed on said planar top surface around the periphery of said mesa contiguous with said base of said mesa; and wherein said semiconductor substrate is semi-insulating in that region directly under and contiguous with said electrode; ohmic contacts formed on the top of said mesa and the bottom of said substrate.
Claim 3
Dependent Claim
11 words
The structure of claim 1 wherein said semiconductor substrate is GaAs.
References Cited (Backward Citations)
US2814853A
Cited
FR1361920A
Cited
US3535170A
Cited
US3855608A
Cited
US3938241A
Cited
US3999281A
Cited
US4129879A
Cited
US4099987A
Cited
US4236166A
Cited
US4262296A
Cited
US4377899A
Cited
GB2064868A
Cited
GB2083947A
Cited
EP0051504A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |