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

• US 7,572,741 B2
• Filed: 09/16/2005
• Issued: 08/11/2009
• Est. Priority Date: 09/16/2005
• Status: Active Grant

• Current Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Agarwal, Anant K., Das, Mrinal K., Palmour, John W., Grider, Dave
• Primary Examiner(s): Landau; Matthew C
• Assistant Examiner(s): LUKE, DANIEL M
• Application Number:
  US11/229,476
• Publication Number:
  US 20090004883A1
• Time in Patent Office: 1,425 Days
• Field of Search: 257/E21.055, 438/788, 438/792, 438/765, 438/787, 438/931
• US Class Current: 438/765
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02236 group IV semiconductor
• CPC Class Codes: H01L 21/02255 formation by thermal treatment H01L21/02252 takes precedence; after treatment of an insulating film H01L21/3105 and subgroups
• CPC Class Codes: H01L 21/049 Conductor-insulator-semiconductor electrodes, e.g. MIS contacts
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31658 by thermal oxidation, e.g. of SiGe
• CPC Class Codes: H01L 21/32105 Oxidation of silicon-containing layers
• CPC Class Codes: Y10S 438/931 Silicon carbide semiconductor

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

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.

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.

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.