USH28H
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chemical vapor deposition (CVD) of cubic silicon carbide SiC
Assignee: UNITED STATES OF AMERICAN AS RESPRESENTED BY SECRETARY OF NAVY
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Filing: 1985-07-03
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Granted: 1986-02-04
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Expires: 2005-07-03
Abstract
Abstract A method for chemical vapor deposition (CVD) of cubic Silicon Carbide (SiC) comprising the steps of etching silicon substrates having one mechanically polished face; depositing a thin buffer layer of cubic SiC formed by reaction between a heated Si substrate and a H 2 C 3 H 8 gas mixture; and depositing SiC on the buffer layer at high temperature using H 2 +C 3 H 8 +SiH 4 mixture.
Inventors
- 👤 Arrigo Addamiano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:58
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/02; C23C16/0272; C23C16/0227; C23C16/22; C23C16/30; C23C16/32; C23C16/325
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
207 words
A method for producing large-area cubic SiC wafers comprising the steps of: wet-etching an Si substrate; heating the Si substrate to between 1370° C. and 1405° C. in H 2 gas; exposing the Si substrate to C 3 H 8 for 5-30 seconds, after temperature equilibrium in the heating step has been reached, to form a buffer layer of single crystal cubic SiC on the Si substrate, the amount of C 3 H 8 being no greater than 1% by volume of the H 2 gas; quenching to room temperature the Si substrate having a cubic SiC buffer layer in a gas of H 2 ; heating the Si substrate with the SiC buffer layer to between 1370° C. and 1405° C. in H 2 gas; exposing the Si substrate having the buffer layer to C 3 H 8 and SiH 4 after thermal equilibrium has been reached in the second heating step for 0.25 to 5 hours to make a thicker layer of cubic SiC, the amount of C 3 H 8 and SiH 4 each being no greater than 1% by volume of the H 2 gas; and quenching the Si substrate having the thicker layer of SiC in H 2 gas to room temperature.
Claim 2
Independent Claim
207 words
A method for producing large-area cubic SiC wafers comprising the steps of: wet-etching an Si substrate; heating the Si substrate to between 1370° C. and 1405° C. in H 2 gas; exposing the Si substrate to C 3 H 8 for 5-30 seconds, after temperature equilibrium in the heating step has been reached, to form a buffer layer of single crystal cubic SiC on the Si substrate, the amount of C 3 H 8 being no greater than 1% by volume of the H 2 gas; quenching to room temperature the Si substrate having a cubic SiC buffer layer in a gas of H 2 ; heating the Si substrate with the SiC buffer layer to between 1370° C. and 1405° C. in H 2 gas; exposing the Si substrate having the buffer layer to C 3 H 8 and SiH 4 after thermal equilibrium has been reached in the second heating step for 0.25 to 5 hours to make a thicker layer of cubic SiC, the amount of C 3 H 8 and SiH 4 each being no greater than 1% by volume of the H 2 gas; and quenching the Si substrate having the thicker layer of SiC in H 2 gas to room temperature.
Claim 3
Dependent Claim
30 words
A method as described in claim 1 wherein the wet-etching step is carried out in a mixture of nitric, hydrofluoric and acetic acid in a volume ratio of 5:3:3, respectively.
Claim 4
Dependent Claim
33 words
A method as described in claim 2 wherein after the wet-etching step, there is an additional step of placing the wet-etched Si substrate on a graphite susceptor inside an rf-induction heated quartz tube.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |