Method of producing stoichiometric, epitaxial, monocrystalline films of silicon carbide at temperatures below 900 degrees centigrade

• US 5,225,032 A
• Filed: 08/09/1991
• Issued: 07/06/1993
• Est. Priority Date: 08/09/1991
• Status: Expired due to Fees

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Golecki, Ilan
• Primary Examiner(s): Kunemund, Robert
• Assistant Examiner(s): Garrett, Felisa
• Application Number:
  US07/742,801
• Time in Patent Office: 697 Days
• Field of Search: 148/DIG. 148, 156/610, 156/612, 156/614, 156/DIG. 64, 156/DIG. 73, 156/DIG. 89, 437/100
• US Class Current: 117/90
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: Y10S 117/902 Specified orientation, shape, crystallography, or size of seed or substrate
• CPC Class Codes: Y10S 148/148 Silicon carbide
• CPC Class Codes: Y10S 438/931 Silicon carbide semiconductor

Abstract

Single crystalline, epitaxial, stoichiometric SiC films are deposited on single crystalline silicon substrates by a procedure which involves first treating the surface of the silicon substrate to remove any surface layer of SiO₂, followed by heating the substrate to temperature within the range of from about 600° to about 1000°0 C. and flowing a stream including a gaseous compound of Si, H and C--free of halogen and containing Si and C in 1:1 atomic ratio--over the heated substrate.

Claims

1. The method for depositing a single crystalline, epitaxial SiC film on a single crystalline Si substrate which comprises, in combination, the steps of

(a) treating the surface of the single crystalline silicon substrate to remove the surface layer of SiO₂ from said silicon substrate;

followed by

(b) heating said substrate to temperature in the range of from about 600°

to about 1000°

C. and flowing a gaseous stream comprising a compound composed of Si, H and C over said heated substrate, to thereby deposit a single crystalline epitaxial SiC film onto said substrate, wherein said compound contains Si and C in 1;

1 atomic ratio.

2. The method of claim 1 wherein said compound composed of Si, H and C is selected from the group consisting of (CH₃ SiH)₂ and H₃ SiCH₃.

3. The method of claim 2 wherein said compound composed of Si, H and C is (CH₃ SiH)₂.

4. The method of claim 2 wherein said compound composed of Si, H and C is H₃ SiCH₃.

5. The method of claim 3 wherein the treatment of the surface of said single crystalline silicon substrate to remove the surface layer of SiO₂ involves the step of subjecting said surface to the action of a reducing agent for SiO₂.

6. The method of claim 4 wherein the treatment of the surface of said single crystalline silicon substrate to remove the surface layer of SiO₂ involves the step of subjecting said surface to the action of a reducing agent for SiO₂.

7. The method of claim 4 wherein the treatment of the surface of said single crystalline silicon substrate to remove the surface layer of SiO₂ involves the step of subjecting said surface to the action of hydrogen at elevated temperature.

8. The method of claim 7 wherein said surface is subjected to the action of hydrogen at temperature within the range of from 600°

to about 1000°

C.

9. The method of claim 6 wherein the treatment of the surface of said single crystalline silicon substrate to remove the surface layer of SiO₂ involves the step of subjecting said surface to the action of hydrogen fluoride.

10. The method of claim 9 wherein the hydrogen fluoride is an aqueous solution of hydrogen fluoride.

11. The method of claim 2 wherein said compound composed of Si, H and C is methylsilane, and wherein said substrate is heated to temperature within the range of from about 700°

to about 900°

C.

12. The method of claim 11 wherein the surface of the single crystalline silicon substrate is in the (111) crystal plane orientation.

13. The method of claim 11 wherein the surface of the single crystalline silicon substrate is in the (110) crystal plane orientation.

14. The method of claim 11 wherein the surface of the single crystalline silicon substrate is in the (100) crystal plane orientation.

15. The method of claim 11 wherein said substrate is heated in the absence of an applied plasma, and the SiC film is deposited in a cubic crystal structure.

16. The method of claim 11 wherein said gaseous stream comprises methylsilane and hydrogen, said substrate is heated in the presence of an applied hydrogen plasma, and the SiC film is deposited in a hexagonal crystal structure.

17. The method of claim 11 with the additional step of including a doping agent for the SiC in the gaseous stream comprising methysilane.

18. The method of claim 17 wherein the doping agent comprises a volatile and thermally decomposible compound of nitrogen, phosphorus or arsenic to obtain an n-type doped SiC film.

19. The method of claim 17 wherein the doping agent comprises a volatile and thermally decomposible compound of boron or aluminum to obtain a p-type doped SiC film.

20. The method of claim 2 with the additional step of treating the Si substrate bearing the single crystalline, epitaxially deposited SiC film to remove said substrate, and to recover the SiC film.

21. The method of claim 20 with the additional step of heating said recovered SiC film to temperature in the range of from about 600°

to about 1000°

C. and flowing a gaseous stream comprising a compound composed of Si, H and C which contains Si and C in 1;

1 atomic ratio over said heated substrate, to thereby deposit additional single crystalline epitaxial SiC onto said SiC film.

22. The method of claim 2 wherein said single crystalline silicon substrate in step (a) is subjected to an atmosphere comprising hydrogen at a temperature in the range of from about 600°

to about 1000°

C., and wherein in step (b) said substrate is heated to temperature within the range of from about 750°

to about 900°

C. and is subjected to gaseous stream comprising hydrogen and methylsilane at a pressure of from about 10^-6 Torr to about 760 Torr.

23. The method of claim 22 wherein said substrate is subjected to said gaseous stream at a pressure of from about 10^-3 to about 760 Torr.

24. The method of claim 23 wherein the single crystalline epitaxial SiC is in a cubic crystal structure.

25. The method of claim 23 wherein the substrate is heated in the presence of an applied hydrogen plasma, and the single crystalline, epitaxial SiC is obtained in a hexagonal crystal structure.

26. The method of claim 23 wherein the SiC film has a thickness of from about 5°

to about 10⁵ Å

.

27. The method of claim 23 sequentially conducted in the absence and presence of one or more doping agents, to obtain alternating doped and undoped layers of SiC on said single crystalline substrate.

28. The method of claim 23 conducted in the presence of an atmosphere comprising a doping agent for the SiC to obtain a doped SiC layer, with the additional step of epitaxially depositing a layer of single crystalline silicon onto said doped SiC layer.

29. The method of claim 28 sequentially repeated to obtain a structure comprising alternating layers, of doped or undoped SiC, and of doped or undoped silicon.