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US5471072A
Expired / Lapsed
US
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Platinum and platinum silicide contacts on β-silicon carbide
Assignee: United States Department of the Navy
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Filing: 1993-12-13
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Granted: 1995-11-28
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Expires: 2013-12-13
Abstract
Abstract Gold, which is the commonly used metallization on β-silicon carbide, is known to degrade at temperatures above 450° C. It also exhibits poor adhesion to silicon carbide. Schottky contacts with platinum metallization have rectifying characteristics similar to contacts with gold metallization. The platinum Schottky contacts remain stable up to 800° C. Adhesion of the platinum deposited at slightly elevated temperatures is also superior to that for gold. Platinum provides a metallization that is physically more rugged and thermally more stable than conventional gold metallization.
Inventors
- 👤 Nicolas A. Papanicolaou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:08
CPC Classifications
H; H10; H10D; H10D8/00; H10D8/01; H10D8/051; H10D62/00; H10D62/80; H10D62/83; H10D62/832; H10D62/8325; H10D64/00; H10D64/01; H10D64/012; H10D64/0121; H10D64/0123; H10D64/60; H10D64/64; Y; Y10; Y10S; Y10S148/00; Y10S148/148; Y10S438/00; Y10S438/931; Y10S438/974
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
34 words
A Schottky contact comprising metallization of platinum on n-type β-silicon carbide, and an interfacial layer including PtSi, said Schottky contact being stable to catastrophic degradation of rectifying characteristics at temperatures up to 800° C.
Claim 2
Dependent Claim
34 words
A Schottky contact comprising metallization of platinum on n-type β-silicon carbide, and an interfacial layer including PtSi, said Schottky contact being stable to catastrophic degradation of rectifying characteristics at temperatures up to 800° C.
Claim 3
Dependent Claim
18 words
A Schottky contact metallization on β-silicon carbide as recited in claim 1 wherein the thickness is 750-1000 angstroms.
Claim 4
Dependent Claim
46 words
A Schottky contact metallization on silicon carbide comprising a contact layer of platinum, an interfacial layer including PtSi, a diffusion barrier layer, and a highly conducting top layer metal, said Schottky contact being stable to catastrophic degradation of rectifying characteristic at temperatures up to 800° C.
Claim 5
Dependent Claim
46 words
A Schottky contact metallization on silicon carbide comprising a contact layer of platinum, an interfacial layer including PtSi, a diffusion barrier layer, and a highly conducting top layer metal, said Schottky contact being stable to catastrophic degradation of rectifying characteristic at temperatures up to 800° C.
Claim 6
Dependent Claim
35 words
A Schottky contact metallization on β-silicon carbide as recited in claim 3 wherein the diffusion barrier is chosen from the group consisting of tungsten and 10%/90% titanium/tungsten alloy in the range of 200-750 angstroms thick.
Claim 7
Dependent Claim
36 words
A Schottky contact metallization on β-silicon carbide as recited in claim 4 wherein the highly conducting top layer metal is chosen from the group consisting of gold and aluminum in the range of 2000-4000 angstroms thick.
Claim 8
Dependent Claim
23 words
A Schottky contact metallization on β-silicon carbide as recited in claim 5 wherein the platinum contact layer is 100 to 3000 angstroms thick.
Claim 9
Dependent Claim
44 words
A Schottky contact metallization on β-silicon carbide as recited in claim 6 wherein the platinum contact layer is 500-1000 angstroms thick, the diffusion barrier is titanium/tungsten alloy of 400-600 angstroms thick and the highly conducting top layer metal is gold of 2500-3500 angstroms thick.
Claim 10
Dependent Claim
47 words
A Schottky contact metallization on β-silicon carbide as recited in claim 7 wherein the platinum contact layer is about 800 angstroms thick, the diffusion barrier is titanium/tungsten alloy of about 500 angstroms thick and the highly conducting top layer metal is gold of about 3000 angstroms thicker
Claim 11
Dependent Claim
67 words
A Schottky contact on β-silicon carbide according to claim 1, said Schottky contact having been produced by a method comprising the steps of: preparing a smooth surface on the β-silicon carbide; depositing a passivant for the Schottky contacts; forming windows in the passivant for the Schottky contacts; cleaning the surface of the B-silicon; heating β-silicon carbide to approximately 140° C.; depositing platinum metallization; and removing unnecessary metallization.
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) | 1998-11-27 | 1999-05-29 | 1999-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-11-27 | 2003-05-29 | 2003-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-11-27 | 2007-05-29 | 2007-11-28 | $7700.00 | Window Closed / Lapsed |