In-situ defect reduction techniques for nonpolar and semipolar (Al, Ga, In)N

• US 8,105,919 B2
• Filed: 04/14/2010
• Issued: 01/31/2012
• Est. Priority Date: 05/09/2006
• 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: Chakraborty, Arpan, Kim, Kwang-Choong, DenBaars, Steven P., Speck, James S., Mishra, Umesh K.
• Primary Examiner(s): Richards, N Drew
• Assistant Examiner(s): Diallo, Mamadou
• Application Number:
  US12/759,903
• Publication Number:
  US 20100193911A1
• Time in Patent Office: 657 Days
• Field of Search: 438/689, 438/483, 257/79, 257/190
• US Class Current: 438/478
• CPC Class Codes: H01L 21/0237 Materials
• 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 21/02516 Crystal orientation
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 33/007 comprising nitride compounds

Abstract

A method for growing reduced defect density planar gallium nitride (GaN) films is disclosed. The method includes the steps of (a) growing at least one silicon nitride (SiN_x) nanomask layer over a GaN template, and (b) growing a thickness of a GaN film on top of the SiN_x nanomask layer.

Claims

1. A method for growing a reduced defect density nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template, comprising:

(a) growing at least one nonpolar or semipolar Al_xGa_yIn_(1-x-y)N layer on top of at least one nanomask layer, which results in the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N layer having a planar top surface that is a nonpolar or semipolar plane and a reduced defect density as compared to a nonpolar or semipolar Al_xGa_yIn_(1-x-y)N layer grown without the nanomask layer.

2. The method of claim 1, wherein the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template is planar and coalesced.

3. The method of claim 1, wherein the nanomask layer is silicon nitride (SiN_x).

4. The method of claim 1, wherein the growth of the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N layer on top of the nanomask layer is a nano lateral epitaxial overgrowth on at least one open pore in the nanomask layer, with the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N layer growing through the open pore and laterally over the nanomask layer.

5. The method of claim 4, wherein the open pore is a nanoscale open pore.

6. The method of claim 1, further comprising growing the nanomask layer over a substrate.

7. The method of claim 1, further comprising growing the nanomask layer over a nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template prior to growing the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N layer.

8. The method of claim 1, wherein the growth of the nanomask layer is in-situ with the growth of the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template.

9. The method of claim 1, wherein the reduced defect nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template is a free standing layer.

10. The method of claim 1, wherein a thicker nanomask layer results in a lower defect density for the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template.

11. The method of claim 1, wherein the nonpolar or semipolar III-nitride layer does not form a coalesced film for the SiN_x nanomask layer having a thickness greater than 1.5 nm.

12. The method of claim 1, wherein the nanomask layer helps in strain relaxation.

13. The method of claim 1, wherein the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template is grown on the nanomask layer at an intermediate growth temperature of approximately 800-1000°

C. to help in further reduction of defect density by increasing three-dimensional island size in the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N layer.

14. The method of claim 1, wherein the reduced defect density template is comprised of GaN.

15. The method of claim 1, wherein the reduced defect density template is comprised of In_xGa_1-xN.

16. The method of claim 1, wherein the reduced defect density template is comprised of Al_xGa_1-xN.

17. The method of claim 1, wherein the reduced defect density template is comprised of Al_xIn_1-xN.

18. The device of claim 1, wherein the reduced defect density nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template has a threading dislocation density less than 9×

10⁹ cm<sup>−

2</sup> and a stacking fault density less than 3×

10⁵ cm<sup>−

1</sup>.

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

20. A device, comprising:

(a) at least one nanomask layer; and

(b) a nonpolar or semipolar Al_xGa_yIn_(1-x-y)N layer grown on top of the nanomask layer and having a planar top surface that is a nonpolar or semipolar plane and a reduced defect density as compared to a nonpolar or semipolar Al_xGa_yIn_(1-x-y)N grown without the nanomask layer.

21. The device of claim 20, wherein the nonpolar or semipolar Al_xGa_yIn_(1-x-y)N template has a threading dislocation density less than 9×

10⁹ cm<sup>−

2</sup> and a stacking fault density less than 3×

10⁵ cm<sup>−

1</sup>.

22. The device of claim 20, wherein the device is an optoelectronic device.

23. The device of claim 20, wherein the device is an electronic device.