US4990994A
Expired / Lapsed
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Electrode structure for silicon carbide semiconductors
Assignee: Sharp Corp
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Filing: 1989-09-05
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Granted: 1991-02-05
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Expires: 2009-09-05
Abstract
Abstract An electrode structure for a silicon carbide single-crystal semiconductor in which the surface of the silicon carbide single-crystal is laminated with a metal layer of titanium, aluminum, chromium or molybdenum, or with the metal layer and an electrically conductive protective layer formed over the metal layer to provide an ohmic electrode.
Inventors
- 👤 Katsuki Furukawa
- 👤 Akira Suzuki
- 👤 Mitsuhiro Shigeta
- 👤 Atsuko Uemoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:16
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/83; H10D62/832; H10D62/8325; H10D64/00; H10D64/60; H10D64/62
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
67 words
In an electrode structure for a silicon carbide single-crystal semiconductor in which the surface of the silicon carbide single-crystal is laminated with an electrode layer, the improvement in which the silicon carbide single-crystal has surface irregularities and the electrode layer comprises a metal layer of titanium, chromium or molybdenum and an electrically conductive protective layer of aluminum, copper and/or nickel formed thereon, to provide an ohmic electrode.
Claim 2
Dependent Claim
67 words
In an electrode structure for a silicon carbide single-crystal semiconductor in which the surface of the silicon carbide single-crystal is laminated with an electrode layer, the improvement in which the silicon carbide single-crystal has surface irregularities and the electrode layer comprises a metal layer of titanium, chromium or molybdenum and an electrically conductive protective layer of aluminum, copper and/or nickel formed thereon, to provide an ohmic electrode.
Claim 3
Dependent Claim
25 words
The electrode structure of claim 1, wherein the silicon carbide single-crystal is an epitaxially grown single crystal having a cubic structure of the β type.
Claim 4
Dependent Claim
18 words
The electrode structure of claim 1, wherein the metal layer is from 200 to 800 Angstroms in thickness.
Claim 5
Dependent Claim
20 words
The electrode structure of claim 1, wherein the electrically conductive protective layer is from 1000 to 3000 Angstroms in thickness.
Claim 6
Dependent Claim
32 words
The electrode structure of claim 1, wherein the metal layer is from 200 to 800 Angstroms in thickness, and the electrically conductive protective layer is from 1000 to 3000 Angstroms in thickness.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-02-04 | 1994-08-06 | 1995-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-04 | 1998-08-06 | 1999-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-04 | 2002-08-06 | 2003-02-05 | $7700.00 | Window Closed / Lapsed |