US4157556A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heterojunction confinement field effect transistor
Assignee: Varian Medical Systems Inc
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Filing: 1977-01-06
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Granted: 1979-06-05
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Expires: 1997-01-06
Abstract
Abstract An improved field-effect transistor is provided by forming the conducting channel boundary opposite the gate electrode as a heterojunction. For example a GaAs conducting channel may be bounded by an AlGaAs layer. The conduction electrons can penetrate the boundary very little and are constrained to the channel layer having good transport properties. The output conductance is reduced and the transconductance increased.
Inventors
- 👤 David R. Decker
- 👤 Ronald L. Moon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:20
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/80; H10D30/87; H10D62/00; H10D62/10; H10D62/17; H10D62/351; H10D62/357; H10D62/80; H10D62/82; H10D62/824
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
86 words
A field-effect transistor comprising: an active layer of semiconductive material, source, gate and drain electrodes on a first side of said active layer, and a semiconductor boundary layer adjoining the second side of said active layer, said boundary layer having a chemical composition different from said active layer and an electrical conductivity substantially lower than said active layer, said semiconductor layer and said active layer forming a heterojunction along said second side, whereby electrons are confined to flow only in said active layer by said heterojunction.
Claim 2
Dependent Claim
86 words
A field-effect transistor comprising: an active layer of semiconductive material, source, gate and drain electrodes on a first side of said active layer, and a semiconductor boundary layer adjoining the second side of said active layer, said boundary layer having a chemical composition different from said active layer and an electrical conductivity substantially lower than said active layer, said semiconductor layer and said active layer forming a heterojunction along said second side, whereby electrons are confined to flow only in said active layer by said heterojunction.
Claim 3
Dependent Claim
15 words
The transistor of claim 1 wherein said active layer is epitaxial with said boundary layer.
Claim 4
Dependent Claim
40 words
The transistor of claim 1 further including a substrate body adjoining said boundary layer on the side opposite said active layer, said substrate body having lower electrical conductivity than said active layer and chemical composition different from said boundary layer.
Claim 5
Dependent Claim
18 words
The transistor of claim 3 wherein said active layer and said boundary layer are epitaxial with said substrate.
Claim 6
Dependent Claim
13 words
The transistor of claim 1 wherein said active layer is n-type gallium arsenide.
Claim 7
Dependent Claim
13 words
The transistor of claim 5 wherein said boundary layer is aluminum gallium arsenide.
Claim 8
Dependent Claim
14 words
The transistor of claim 5 wherein said boundary layer is indium gallium arsenide phosphide.
Claim 9
Dependent Claim
13 words
The transistor of claim 3 wherein said substrate body is p-type gallium arsenide.
Claim 10
Dependent Claim
17 words
The transistor of claim 8 wherein said p-type GaAs is doped with Ge, Zn, Cd or Mg.
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) | 1982-06-04 | 1982-12-04 | 1983-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-04 | 1986-12-04 | 1987-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-04 | 1990-12-04 | 1991-06-05 | $7700.00 | Window Closed / Lapsed |