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

• US 20080113496A1
• Filed: 09/14/2007
• Published: 05/15/2008
• 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: Keller, Stacia, Mishra, Umesh Kumar, Fichtenbaum, Nicholas A.
• Granted Patent: US 7,566,580 B2
• Time in Patent Office: Days
• US Class Current: 438/481
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: H01L 21/0237 Materials
• 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 21/0254 Nitrides
• CPC Class Codes: H01L 21/0257 Doping during depositing
• 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 growing an N-face group III nitride film, comprising:

(a) providing 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, l are miller indices; and

(b) growing the N-face group III-nitride film on the growth surface, wherein the N-face group III-nitride film is smoother than an N-face group III-nitride film grown on a substrate without a misorientation angle.

2. 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.

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

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

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

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

7. The method of claim 1, wherein the N-face group III-nitride film is grown on a nitridized misoriented substrate.

8. The method of claim 1, further comprising forming an AlN layer on the misoriented substrate and growing the N-face group III-nitride film on the AlN layer.

9. The method of claim 8, wherein a (Al,Ga,In)N nucleation layer is deposited onto the AlN layer using a step flow growth mode.

10. The method of claim 8, wherein the AlN layer sets an N-polarity for subsequently deposited group III-nitride layers.

11. The method of claim 7, wherein the misoriented substrate is a sapphire substrate.

12. The method of claim 11, further comprising depositing a group III-nitride nucleation layer on an AlN layer formed on the sapphire substrate due to the nitridization, and growing the N-face group III-nitride film on the group III-nitride nucleation layer.

13. The method of claim 12, wherein the group III-nitride nucleation layer is deposited using a step flow growth mode.

14. The method of claim 12, wherein the group III-nitride nucleation layer is at least partially doped.

15. The method of claim 14, wherein the growing of the N-face group III-nitride film comprises:

(a) doping and growing, on the nucleation layer, a first N-face group III nitride layer, and

(b) growing a second N-face group III-nitride layer on the first N-face group-III layer so that at least part of the second N-face group III-nitride layer is doped.

16. The method of claim 8, wherein the misoriented substrate is a polished Carbon Polar Silicon Carbide substrate.

17. The method of claim 16, further comprising depositing a group III-nitride layer having a changing composition on the AlN layer, wherein an Al composition of the group III-nitride layer having the changing composition is graded from AlN to GaN.

18. The method of claim 17, wherein the graded group III-nitride layer is at least partially doped.

19. The method of claim 18, wherein the growing of the group III-nitride layer having an N-face comprises:

(a) doping and growing, on the graded group III-nitride layer, a first group III-nitride layer having an N-face and

(b) growing a second group III-nitride layer having an N-face, so that at least part of the second group III-nitride layer having an N-face is doped.

20. A device fabricated using the method of claim 1.

21. A method for creating a group III-nitride film with an abrupt p-type doping profile, comprising

(a) providing 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, l are miller indices;

and

(b) growing the N-face group III-nitride film having an abrupt p-type doping profile on the growth surface, wherein the group III-nitride film having an N-face is smoother than an N-face group III-nitride film grown on a substrate without a misorientation angle.

22. A method for enhancing charge transport properties of a nitride device, comprising:

fabricating the nitride device using N-face nitride layers 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, l are miller indices; and

aligning a channel of the nitride device substantially perpendicular to a misorientation direction of the misoriented N-face (Al,Ga,In)N layer grown on a misoriented substrate, wherein charge transport properties are enhanced in the misorientation direction.