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US5270252A
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Method of forming platinum and platinum silicide schottky contacts on beta-silicon carbide
Assignee: United States Department of the Navy
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Filing: 1992-07-28
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Granted: 1993-12-14
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Expires: 2012-07-28
Abstract
Abstract Platinum Schottky contacts remaining stable up to 800° C. have been produced. The adhesion of the platinum deposited at slightly elevated temperatures is good. Platinum provides a metallization that is physically rugged and thermally stable. The Schottky contacts are made on B-Silicon carbide.
Inventors
- 👤 Nicolas A. Papanicolaou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:50
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: 12
Claim 1
Independent Claim
54 words
A method of forming a Schottky contact on β-silicon carbide comprising the steps of: providing β-silicon carbide; preparing a smooth surface on the β-silicon carbide; depositing a passivant for a Schottky contact; cleaning the surface of the β-silicon carbide; heating said β-silicon carbide to approximately 140° C.; depositing platinum metallization; and removing unnecessary metallization.
Claim 2
Independent Claim
54 words
A method of forming a Schottky contact on β-silicon carbide comprising the steps of: providing β-silicon carbide; preparing a smooth surface on the β-silicon carbide; depositing a passivant for a Schottky contact; cleaning the surface of the β-silicon carbide; heating said β-silicon carbide to approximately 140° C.; depositing platinum metallization; and removing unnecessary metallization.
Claim 3
Dependent Claim
48 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 1 wherein preparing a smooth surface comprises: mechanically polishing the surface of the β-silicon carbide; oxidizing the surface of the β-silicon carbide; and treating the surface of the β-silicon carbide with an acid wash.
Claim 4
Dependent Claim
34 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 2 wherein mechanically polishing comprises polishing with a 0.1 micron diamond paste on a nylon polishing pad for 6 hours.
Claim 5
Dependent Claim
30 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 3 wherein oxidizing comprises oxidizing in a wet, oxygen-containing atmosphere for 5 hours at 1150° C.
Claim 6
Dependent Claim
32 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 4 wherein treating with an acid wash comprises treating with a 1:1 solution of hydrofluoric acid and water.
Claim 7
Dependent Claim
27 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 5 wherein depositing a passivant comprises oxidizing the surface of the β-silicon carbide.
Claim 8
Dependent Claim
50 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 6 wherein said step of forming a window in the passivant comprises using a photolithographic and lift-off process to form a photoresist mask and etching a pattern with a buffered HF solution using the photoresist mask.
Claim 9
Dependent Claim
39 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 7 wherein the step of forming a window comprises using said photolithographic and lift-off process to form said photoresist mask as a positive photoresist mask.
Claim 10
Dependent Claim
29 words
A method of forming a Schottky contact to a β-silicon carbide as recited in claim 7 wherein cleaning the surface comprises: rinsing a deionized water; and drying in nitrogen.
Claim 11
Dependent Claim
29 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 9 wherein said platinum metallization is deposited by e-beam evaporation, RF sputtering or magnetron sputtering.
Claim 12
Dependent Claim
38 words
A method of forming a Schottky contact to β-silicon carbide as recited in claim 10 wherein the step of removing unnecessary metallization comprises soaking the photoresist in acetone and placing it in a ultrasonic cleaner for 30 seconds.
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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) | 1996-12-13 | 1997-06-14 | 1997-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-13 | 2001-06-14 | 2001-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-13 | 2005-06-14 | 2005-12-14 | $7700.00 | Window Closed / Lapsed |