US5028968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiation hard GaAs high electron mobility transistor
Assignee: Aerospace Corp
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Filing: 1990-01-02
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Granted: 1991-07-02
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Expires: 2010-01-02
Abstract
Abstract The incorporation of a GaAs layer that is intentionally p-doped into a standard HEMT device structure has been shown to produce a HEMT transistor with greatly enhanced radiation hardness under exposure to neutron radiation.
Inventors
- 👤 Michael J. O'Loughlin
- 👤 Richard J. Krantz
- 👤 Walter L. Bloss, III
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:56
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/40; H10D30/47; H10D30/471; H10D30/475; H10D30/4755
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
167 words
A neutron radiation hardened gallium arsenide and aluminum gallium arsenide high electron mobility transistor (HEMT), comprising a) a semi-insulating gallium arsenide substrate; b) a doped buffer layer of GaAs, doped with an acceptor impurity supported by the substrate; c) an undoped layer about 200 angstroms thick of GaAs supported by the doped buffer layer; d) an undoped spacer layer of Al 0 .25 Ga 0 .75 As supported by the undoped layer; e) a first doped layer of Al 0 .25 Ga 0 .75 As doped with a donor impurity supported by the substrate layer; f) a second doped layer of GaAs doped with a donor impurity supported by the first doped layer of Al 0 .25 Ga 0 .75 As to facilitate the making of ohmic contact; g) a gate of Ti/Pd/Au deposited on the first doped layer by etching through the second doped GaAs layer; h) a source and drain electrode of alloyed AuGe/Ni/Au deposited on and sintered to the second doped layer of GaAs.
Claim 2
Dependent Claim
167 words
A neutron radiation hardened gallium arsenide and aluminum gallium arsenide high electron mobility transistor (HEMT), comprising a) a semi-insulating gallium arsenide substrate; b) a doped buffer layer of GaAs, doped with an acceptor impurity supported by the substrate; c) an undoped layer about 200 angstroms thick of GaAs supported by the doped buffer layer; d) an undoped spacer layer of Al 0 .25 Ga 0 .75 As supported by the undoped layer; e) a first doped layer of Al 0 .25 Ga 0 .75 As doped with a donor impurity supported by the substrate layer; f) a second doped layer of GaAs doped with a donor impurity supported by the first doped layer of Al 0 .25 Ga 0 .75 As to facilitate the making of ohmic contact; g) a gate of Ti/Pd/Au deposited on the first doped layer by etching through the second doped GaAs layer; h) a source and drain electrode of alloyed AuGe/Ni/Au deposited on and sintered to the second doped layer of GaAs.
Claim 3
Dependent Claim
31 words
The hardened HEMT claimed in claim 1 wherein the acceptor impurity is Be and the concentration of Be in the doped buffer layer is about 1× 10 16 cm -3 .
Claim 4
Dependent Claim
36 words
The hardened HEMT as claimed in claim 1 wherein the donor impurity of the first doped layer is Si and the concentration of Si in the first doped layer is about 1×10 18 cm -3 .
Claim 5
Dependent Claim
35 words
The hardened HEMT claimed in claim 1 wherein the donor impurity of the second doped layer is Si and the concentration of Si in the second doped layer is about 2×10 18 cm -3 .
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) | 1994-07-01 | 1994-12-31 | 1995-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-01 | 1998-12-31 | 1999-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-01 | 2002-12-31 | 2003-07-02 | $7700.00 | Window Closed / Lapsed |