US4587540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
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 18:59
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.
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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) | 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 |