US4948752A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making sagfets on buffer layers
Assignee: Frontgrade Technologies Inc
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Filing: 1990-01-31
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Granted: 1990-08-14
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Expires: 2010-01-31
Abstract
Abstract A composite buffer layer is formed with a layer of GaAs on a semi-insulating GaAs substrate. Next a short period superlattice is formed followed by another GaAs layer, whereon is formed a first AlGaAs layer having a first mole fraction of Al and a second AlGaAs layer having a second mole fraction of Al higher than the first mole fraction. As intrinsic GaAs channel layer is formed on the second AlGaAs layer.
Inventors
- 👤 Arthur E. Geissberger
- 👤 Robert A. Sadler
- 👤 Gregory E. Menk
- 👤 Matthew L. Balzan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:40
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/351; H10D62/357; Y; Y10; Y10S; Y10S148/00; Y10S148/072; Y10S148/16; Y10S438/00; Y10S438/936; Y10S438/938
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
149 words
A method of manufacture for a GaAs based semiconductor product comprising; providing a semiconductor substrate having a first major surface generally aligned with the (1,0,0) plane of a GaAs surface layer of said substrate; providing a first epitaxial layer of GaAs on said first major surface; providing an AlAs/GaAs superlattice on said first epitaxial layer of GaAs; providing a second epitaxial layer of GaAs on said superlattice; providing a compositionally graded buffer layer of AlGaAs commencing with a first mole fraction of Al and ending with a second mole fraction of Al higher than said first mole fraction; providing a second layer of AlGaAs on said compositionally graded buffer layer of AlGaAs, said second layer of AlGaAs having a uniform mole fraction of Al substantially equal to said second mole fraction and including a top surface; providing a third epitaxial layer of GaAs on said second layer of AlGaAs.
Claim 2
Independent Claim
149 words
A method of manufacture for a GaAs based semiconductor product comprising; providing a semiconductor substrate having a first major surface generally aligned with the (1,0,0) plane of a GaAs surface layer of said substrate; providing a first epitaxial layer of GaAs on said first major surface; providing an AlAs/GaAs superlattice on said first epitaxial layer of GaAs; providing a second epitaxial layer of GaAs on said superlattice; providing a compositionally graded buffer layer of AlGaAs commencing with a first mole fraction of Al and ending with a second mole fraction of Al higher than said first mole fraction; providing a second layer of AlGaAs on said compositionally graded buffer layer of AlGaAs, said second layer of AlGaAs having a uniform mole fraction of Al substantially equal to said second mole fraction and including a top surface; providing a third epitaxial layer of GaAs on said second layer of AlGaAs.
Claim 3
Dependent Claim
54 words
A method of manufacture for a GaAs based semiconductor product as claimed in claim 1, further comprising; smoothing the top surface of said second layer of AlGaAs by exposing said surface to elevated temperatures for a time sufficient to reduce surface variations prior to said step of providing a third epitaxial layer of GaAs.
Claim 4
Dependent Claim
32 words
A method of manufacture for a GaAs based semiconductor product as claimed in claim 1, wherein; said second layer of AlGaAs having a thickness of between about 0.5 micrometer and 1.0 micrometer.
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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) | 1993-08-13 | 1994-02-12 | 1994-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-13 | 1998-02-12 | 1998-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-13 | 2002-02-12 | 2002-08-14 | $7700.00 | Window Closed / Lapsed |