METHOD FOR HETEROEPITAXIAL GROWTH OF HIGH-QUALITY N-FACE GaN, InN, AND AlN AND THEIR ALLOYS BY METAL ORGANIC CHEMICAL VAPOR DEPOSITION

• US 20090246944A1
• Filed: 05/15/2009
• Published: 10/01/2009
• Est. Priority Date: 11/15/2006
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Fichtenbaum, Nicholas K., Keller, Stacia, Mishra, Umesh K.
• Granted Patent: US 8,193,020 B2
• Time in Patent Office: Days
• US Class Current: 438/478
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: H01L 21/02378 Silicon carbide
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02538 Group 13/15 materials
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02573 Conductivity type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD

Abstract

Methods for the heteroepitaxial growth of smooth, high quality films of N-face GaN film grown by MOCVD are disclosed. Use of a misoriented substrate and possibly nitridizing the substrate allow for the growth of smooth N-face GaN and other Group III nitride films as disclosed herein. The present invention also avoids the typical large (μm sized) hexagonal features which make N-face GaN material unacceptable for device applications. The present invention allows for the growth of smooth, high quality films which makes the development of N-face devices possible.

Claims

1. A method for forming an N-polar group III-nitride layer, comprising:

growing a transition layer on a growth surface of a substrate, wherein the growth surface has a misorientation angle between 0.5 and 10 degrees relative to a miller indexed crystallographic plane [h, i, k, l] of the substrate, where h, i, k, l are miller indices; and

growing an N-polar group III-nitride layer on the transition layer;

wherein an atomic structure of a surface of the transition layer adjacent to the N-polar group III-nitride layer results in III-N layers grown on top of the transition layer being oriented in an N-polar direction.

2. The method of claim 1, further including inserting a Group III-polar III-nitride layer between the substrate and the transition layer.

3. The method of claim 1, further including inserting two or more Group III-polar III-nitride layers between the substrate and the transition layer.

4. The method of claim 2, wherein the N-polar group III-nitride layer is smoother than an N-polar group III-nitride layer grown on a substrate without a misorientation angle in the growth surface.

5. The method of claim 2, wherein the transition layer is doped with magnesium.

6. The method of claim 2, wherein a portion of the transition layer adjacent to a first surface of the transition layer is Ga-polar and a portion of the transition layer adjacent to a second surface of the transition layer is N-polar.

7. The method of claim 5, wherein the first surface is adjacent to the Group III-polar III-nitride layer and the second surface is adjacent to the N-polar group III-nitride layer.

8. The method of claim 2, further including growing one or more additional N-polar III-nitride layers on top of the N-polar group III-nitride layer.

9. The method of claim 2, further including inserting one or more additional III-polar III-nitride layers between the on top of the N-polar group III-nitride layer.

10. The method of claim 2, wherein the miller indices are h=1, i=0, k=0 and l=−

1 and the substrate is silicon carbide.

11. The method of claim 2, wherein the miller indices are h=0, i=0, k=0 and l=1 and the substrate is sapphire.

12. The method of claim 2, wherein the miller indices are h=1, k=1, l=1 and the substrate is silicon.

13. The method of claim 2, wherein the substrate is (001) Si.

14. The method of claim 2, wherein the growing is by Metal Organic Chemical Vapor Deposition (MOCVD).

15. The method of claim 2, wherein the substrate is a nitridized misoriented substrate.

16. The method of claim 1, wherein the N-polar group III-nitride layer is smoother than an N-polar group III-nitride layer grown on a substrate without a misorientation angle in the growth surface.

17. The method of claim 1, wherein the transition layer is doped with magnesium.

18. The method of claim 1, wherein the miller indices are h=1, i=0, k=0 and l=−

1 and the substrate is silicon carbide.

19. The method of claim 1, wherein the miller indices are h=0, i=0, k=0 and l=1 and the substrate is sapphire.

20. The method of claim 1, wherein the miller indices are h=1, k=1, l=1 and the substrate is silicon.

21. The method of claim 1, wherein the substrate is (001) Si.

22. The method of claim 1, wherein the growing is by Metal Organic Chemical Vapor Deposition (MOCVD).

23. The method of claim 1, wherein the substrate is a nitridized misoriented substrate.

24. A method for altering charge transport properties in a channel of a nitride device, comprising:

fabricating the nitride device using N-face nitride layers grown on a transition layer which is grown on a substrate having a growth surface with a misorientation angle between 0.5 and 10 degrees relative to a miller indexed crystallographic plane [h, i, k, l] of the substrate, where h, i, k, and l are miller indices, wherein an atomic structure of a surface of the transition layer adjacent to the N-face nitride layers results in III-N layers grown on top of the transition layer being oriented in an N-polar direction; and

orienting the channel of the nitride device with respect to a misorientation direction of the misoriented N-face (Al, Ga, In)N layer grown on a misoriented substrate to alter the charge transport properties of the channel.

25. The method of claim 24, wherein the N-face nitride layers are smoother than N-face nitride layers grown on a substrate without a misorientation angle in the growth surface.

26. The method of claim 24, wherein the transition layer is doped with magnesium.