US4173764A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field effect transistor on a support having a wide forbidden band
Assignee: Thales SA
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Filing: 1978-04-04
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Granted: 1979-11-06
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Expires: 1998-04-04
Abstract
Abstract A field effect transistor deposited upon a substrate having a wide forbidden band comprises an active layer of n-type conductivity which forms a heterojunction with the substrate. Since the subjacent material has a forbidden band higher than the forbidden band of the active layer, the formation of electronic currents between the source and the drain and in the substrate is avoided.
Inventors
- 👤 Baudouin DE Cremoux
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:00
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/351; H10D62/357; H10D30/00; H10D30/80; H10D30/87; H10D62/80; H10D62/82; H10D62/824
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
79 words
A field effect transistor comprising: a substrate layer; an active semiconducting layer deposited on said substrate layer, and three electrodes disposed on the surface of said active layer respectively forming source, gate and drain electrodes, the gate electrode forming a rectifying junction with said active layer, and said active layer forming a heterojunction with said substrate layer, said substrate layer being made of a semiconductor material having a higher forbidden energy band gap than that of said active layer.
Claim 2
Dependent Claim
79 words
A field effect transistor comprising: a substrate layer; an active semiconducting layer deposited on said substrate layer, and three electrodes disposed on the surface of said active layer respectively forming source, gate and drain electrodes, the gate electrode forming a rectifying junction with said active layer, and said active layer forming a heterojunction with said substrate layer, said substrate layer being made of a semiconductor material having a higher forbidden energy band gap than that of said active layer.
Claim 3
Dependent Claim
12 words
A transistor as claimed in claim 1, wherein said substrate is semi-insulating.
Claim 4
Dependent Claim
24 words
A transistor as claimed in claim 1, wherein said gate is made of a metal which forms a rectifying contact with said active layer.
Claim 5
Dependent Claim
25 words
A transistor as claimed in claim 1, wherein said gate is formed by a semiconducting layer which forms a rectifying junction with said active layer.
Claim 6
Dependent Claim
32 words
A transistor according to claim 1, wherein said active layer is made of gallium arsenide and the substrate layer is made of a compound having the formula Ga 1-x Al x As.
Claim 7
Dependent Claim
92 words
A field effect transistor comprising: a semiconductor substrate layer; a buffer semiconductor layer deposited on the surface of said substrate layer; an active semiconductor layer deposited on the surface of said buffer layer; and three electrodes disposed on the surface of said active layer respectively forming source, gate and drain electrodes, the gate electrode forming a reactifying junction with said active layer, and said active layer forming a heterojunction with said buffer layer, said buffer layer being made of a material having a higher forbidden energy band gap than said active layer.
Claim 8
Dependent Claim
92 words
A field effect transistor comprising: a semiconductor substrate layer; a buffer semiconductor layer deposited on the surface of said substrate layer; an active semiconductor layer deposited on the surface of said buffer layer; and three electrodes disposed on the surface of said active layer respectively forming source, gate and drain electrodes, the gate electrode forming a reactifying junction with said active layer, and said active layer forming a heterojunction with said buffer layer, said buffer layer being made of a material having a higher forbidden energy band gap than said active layer.
Claim 9
Dependent Claim
16 words
A transistor according to claim 6 wherein said substrate is a semi-insulating layer of gallium arsenide.
Claim 10
Dependent Claim
23 words
A transistor according to claim 6 wherein said buffer layer is made of a compound having the formula Ga 1-x Al x As.
Claim 11
Dependent Claim
14 words
A transistor according to claim 8 wherein said substrate is made of gallium arsenide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-11-05 | 1983-05-07 | 1983-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-05 | 1987-05-07 | 1987-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-05 | 1991-05-07 | 1991-11-06 | $7700.00 | Window Closed / Lapsed |