Patent US4380774A successfully refreshed from Google Patents.
US4380774A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-performance bipolar microwave transistor
Assignee: United States Department of the Navy
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Filing: 1980-12-19
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Granted: 1983-04-19
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Expires: 2000-12-19
Abstract
Abstract A high-frequency transistor and method of making same wherein the parasiticapacitance between base and collector is reduced. The collector layer of GaAs is impregnated with boron ions to form an insulative region under the base contact structure thereby reducing the capacitance in this region and leaving only the region underlying the emitter structure as the active transistor region.
Inventors
- 👤 Nax N. Yoder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:52
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/80; H10D10/821; H10D62/00; H10D62/10; H10D62/113; H10D62/115; H10D62/13; H10D62/137; H10D62/138; H10D62/165; H10D64/00; H10D64/20; H10D64/23; H10D64/231; H10D64/27; H10D64/281
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
166 words
An improved bipolar transistor of the type having a collector layer lying on one side of a substrate and an ohmic contact lying on the other side thereof, a base layer lying on the collector layer, an emitter structure including a tunnel barrier layer lying on a center region of the base layer, an emitter layer lying on the tunnel barrier layer and another ohmic contact lying on the emitter layer, and a base contact structure including a contact layer lying on outer regions of the base layer and a metal layer lying on the contact layer, the emitter and base contact structures being spaced from each other, wherein the improvement comprises: forming a semi-insulative region in the collector layer underlying the base contact structure, so that the region through which charge carriers travel from the emitter structure through the base layer into the collector layer is restricted substantially to the center region of the base layer underlying the tunnel barrier layer of the emitter structure.
Claim 2
Dependent Claim
166 words
An improved bipolar transistor of the type having a collector layer lying on one side of a substrate and an ohmic contact lying on the other side thereof, a base layer lying on the collector layer, an emitter structure including a tunnel barrier layer lying on a center region of the base layer, an emitter layer lying on the tunnel barrier layer and another ohmic contact lying on the emitter layer, and a base contact structure including a contact layer lying on outer regions of the base layer and a metal layer lying on the contact layer, the emitter and base contact structures being spaced from each other, wherein the improvement comprises: forming a semi-insulative region in the collector layer underlying the base contact structure, so that the region through which charge carriers travel from the emitter structure through the base layer into the collector layer is restricted substantially to the center region of the base layer underlying the tunnel barrier layer of the emitter structure.
Claim 3
Dependent Claim
44 words
The improved bipolar transistor of claim 1 wherein the collector layer is formed from GaAs, and the semi-insulative region in the collector layer is formed by implanting and subsequently annealing the collector layer underlying the base contact structure with boron-ions to a predetermined density.
Claim 4
Dependent Claim
22 words
The improved bipolar transistor of claim 2 wherein the predetermined density of the boron-ions is at least 1×10 16 /cm 3 .
Claim 5
Dependent Claim
30 words
The improved bipolar transistor of claim 3 wherein the semi-insulative region is deeper than the depth of the collector layer and extends into the one side of the underlying substrate.
References Cited (Backward Citations)
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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) | 1986-04-18 | 1986-10-18 | 1987-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-18 | 1990-10-18 | 1991-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-18 | 1994-10-18 | 1995-04-19 | $7700.00 | Window Closed / Lapsed |