IP Library Granted Patent US 7,572,741
Granted Patent B2
US 7,572,741 · App. 11/229,476 · Granted Aug 11, 2009

Methods of fabricating oxide layers on silicon carbide layers utilizing atomic oxygen

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Quick Facts
Patent No.
US 7,572,741
App. No.
11/229,476
Granted
Aug 11, 2009
Kind
B2
Abstract

Methods of forming oxide layers on silicon carbide layers are disclosed, including placing a silicon carbide layer in a chamber such as an oxidation furnace tube that is substantially free of metallic impurities, heating an atmosphere of the chamber to a temperature of about 500 ° C. to about 1300 ° C., introducing atomic oxygen in the chamber, and flowing the atomic oxygen over a surface of the silicon carbide layer to thereby form an oxide layer on the silicon carbide layer. In some embodiments, introducing atomic includes oxygen providing a source oxide in the chamber and flowing a mixture of nitrogen and oxygen gas over the source oxide. The source oxide may comprise aluminum oxide or another oxide such as manganese oxide. Some methods include forming an oxide layer on a silicon carbide layer and annealing the oxide layer in an atmosphere including atomic oxygen.

Claims (30)

1. A method of forming an oxide layer on a silicon carbide layer, comprising:

placing a silicon carbide layer in a chamber substantially free of metallic impurities;

heating an atmosphere of the chamber to a temperature of about 500° C. to about 1300° C.;

introducing atomic oxygen in the chamber, wherein introducing atomic oxygen comprises providing a source oxide in the chamber and flowing nitrogen gas over the source oxide under conditions selected to liberate atomic oxygen from the source oxide; and

flowing the atomic oxygen over a surface of the silicon carbide layer to thereby form an oxide layer on the silicon carbide layer.

2. The method of claim 1 , wherein the source oxide comprises aluminum oxide.

3. The method of claim 1 , wherein the source oxide comprises manganese oxide.

4. The method of claim 1 , wherein the source oxide is substantially free of metallic impurities.

5. The method of claim 1 , wherein the source oxide comprises a porous sapphire wafer.

6. The method of claim 1 , further comprising:

implanting a sapphire wafer with non-metallic impurities to form a porous sapphire wafer; and

placing the porous sapphire wafer in the chamber, wherein the porous sapphire wafer comprises the source oxide.

7. The method of claim 1 , wherein the chamber comprises an oxidation furnace tube.

8. The method of claim 1 , wherein heating an atmosphere of the chamber comprises heating an atmosphere of the chamber to a temperature of about 1000° C. to about 1100° C.

9. A method of forming an oxide layer on a silicon carbide layer, comprising:

forming an oxide layer on a silicon carbide layer;

placing the silicon carbide layer with the oxide layer thereon in a chamber substantially free of metallic impurities;

heating an atmosphere of the chamber to a temperature of about 500° C. to about 1300° C.;

introducing atomic oxygen in the chamber, wherein introducing atomic oxygen comprises providing a source oxide in the chamber; and flowing nitrogen gas over the source oxide under conditions selected to liberate atomic oxygen from the source oxide; and

flowing the atomic oxygen over a surface of the silicon carbide layer.

10. The method of claim 9 , wherein the source oxide comprises aluminum oxide.

11. The method of claim 9 , wherein the source oxide comprises manganese oxide.

12. The method of claim 9 , wherein the source oxide is substantially free of metallic impurities.

13. The method of claim 9 , wherein the source oxide comprises a porous sapphire wafer.

14. The method of claim 9 , further comprising:

implanting a sapphire wafer with non-metallic impurities to form a porous sapphire wafer; and

placing the porous sapphire wafer in the chamber, wherein the porous sapphire wafer comprises the source oxide.

15. The method of claim 9 , wherein the chamber comprises an oxidation furnace tube.

16. The method of claim 9 , wherein heating an atmosphere of the chamber comprises heating an atmosphere of the chamber to a temperature of about 1000° C. to about 1100° C.

17. The method of claim 1 , wherein flowing nitrogen gas over the source oxide further comprises nitriding the source oxide to form a nitrided source oxide.

Assignments (7)
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Mar 26, 2026
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 075280/0919 →
RELEASE OF SECURITY INTEREST IN INTELLECTUAL PROPERTY COLLATERAL AT REEL/FRAME NO. 64185/0755 Recorded Sep 30, 2025
From: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
To: WOLFSPEED, INC.
Reel/Frame 072989/0001 →
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Sep 30, 2025
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 072992/0113 →
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Sep 30, 2025
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 072992/0467 →
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Sep 30, 2025
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 072992/0588 →
NOTICE OF GRANT OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Recorded Sep 30, 2025
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION, AS COLLATERAL AGENT
Reel/Frame 072992/0381 →
SECURITY INTEREST Recorded Jun 30, 2023
From: WOLFSPEED, INC.
To: U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION
Reel/Frame 064185/0755 →