Method for growth of semipolar (Al,In,Ga,B)N optoelectronic devices

• US 8,203,159 B2
• Filed: 09/24/2010
• Issued: 06/19/2012
• Est. Priority Date: 02/17/2006
• 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: Zhong, Hong, Kaeding, John F., Sharma, Rajat, Speck, James S., DenBaars, Steven P., Nakamura, Shuji
• Primary Examiner(s): Louie, Wai Sing
• Application Number:
  US12/889,787
• Publication Number:
  US 20110012234A1
• Time in Patent Office: 634 Days
• Field of Search: 257/79, 257/95, 257/98, 257/103
• US Class Current: 257/95
• CPC Class Codes: C30B 25/186 being specially pre-treated by, e.g. chemical or physical means
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: H01L 21/02389 Nitrides
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02647 Lateral overgrowth
• CPC Class Codes: H01L 21/02658 Pretreatments cleaning in general H01L21/02041
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 29/778 with two-dimensional charge carrier gas channel, e.g. HEMT ; with two-dimensional charge-carrier layer formed at a heterojunction interface H01L29/803 takes precedence
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A method of fabricating an optoelectronic device, comprising growing an active layer of the device on an oblique surface of a suitable material, wherein the oblique surface comprises a facetted surface. The present invention also discloses a method of fabricating the facetted surfaces. One fabrication process comprises growing an epitaxial layer on a suitable material, etching the epitaxial layer through a mask to form the facets having a specific crystal orientation, and depositing one or more active layers on the facets. Another method comprises growing a layer of material using a lateral overgrowth technique to produce a facetted surface, and depositing one or more active layers on the facetted surfaces. The facetted surfaces are typically semipolar planes.

Claims

1. An optoelectronic device, comprising:

(a) one or more first oblique or facetted surfaces formed on a substrate or template, wherein;

the first oblique or facetted surfaces are one or more semi-polar planes or one or more non-polar planes, and

the first oblique or facetted surfaces are etched surfaces; and

(b) one or more active layers formed epitaxially on the first oblique or facetted surfaces or on one or more epitaxial layers formed on the first oblique or facetted surfaces, wherein;

at least one of the active layers includes Indium and has a top surface comprising one or more second oblique or facetted surfaces, and

the second oblique or facetted surfaces are one or more semi-polar planes or one or more non-polar planes;

(c) wherein at least one of the active layers, epitaxial layers, substrate, or template, is comprised of (Al, Ga, In)N-based material.

2. The device of claim 1, wherein the surface of the substrate or template is c-plane before the first oblique or facetted surfaces are formed.

3. The device of claim 1, wherein the first oblique or facetted surfaces do not all have the same orientation.

4. The device of claim 1, wherein the first oblique or facetted surfaces have an inclination angle in a range from 25 to 50 degrees.

5. The device of claim 1, wherein the first oblique or facetted surfaces are formed with an inclination angle larger than desired because subsequent layers deposited on the first oblique or facetted surfaces reduce the inclination angle.

6. The device of claim 1, wherein:

(1) the first oblique or facetted surfaces have a maximum depth in a range between 1 nanometer and 10 microns, which determines a surface area of the first oblique or facetted surfaces; and

(2) the surface area of the first oblique or facetted surfaces have a width in a range between 3 and 10 microns, which determines an angle of inclination of the first oblique or facetted surfaces.

7. The device of claim 1, wherein the first oblique or facetted surfaces are sidewalls or facets of trenches, grooves, or pits in the surface of the III-substrate or template.

9. The method of claim 1, wherein the lateral overgrowth is lateral epitaxial overgrowth, side-wall epitaxial lateral overgrowth (SELO), or cantilevered epitaxial lateral overgrowth (CELO).

10. The optoelectronic device of claim 1, further comprising electrical contacts such that current is confined to areas of the second oblique or facetted surfaces with a desired inclination angle.

12. The optoelectronic device of claim 1, wherein the second oblique or facetted surfaces are the one or more semi-polar planes.

13. The optoelectronic device of claim 1, wherein the second oblique or facetted surfaces are the one or more non-polar planes.

14. The optoelectronic device of claim 1, wherein the at least one active layer comprises a quantum well.

8. An optoelectronic device, comprising:

(a) one or more first oblique or facetted surfaces formed on a substrate or template, wherein;

the first oblique or facetted surfaces are one or more semi-polar planes or one or more non-polar planes, and

the first oblique or facetted surfaces are surfaces of a lateral overgrowth on the surface of the substrate or template; and

(b) one or more active layers formed epitaxially on the first oblique or facetted surfaces or on one or more epitaxial layers formed on the first oblique or facetted surfaces, wherein;

at least one of the active layers includes Indium and has a top surface comprising one or more second oblique or facetted surfaces, and

the second oblique or facetted surfaces are one or more semi-polar planes or one or more non-polar planes;

(c) wherein at least one of the active layers, epitaxial layers, substrate, or template, is comprised of (Al, Ga, In)N-based material.

11. The optoelectronic device of claim 8, further comprising electrical contacts such that current is confined to areas of the second oblique or facetted surfaces with a desired inclination angle.

15. The optoelectronic device of claim 8, wherein the second oblique or facetted surfaces are the one or more semi-polar planes.

16. The optoelectronic device of claim 8, wherein the second oblique or facetted surfaces are the one or more non-polar planes.

17. The optoelectronic device of claim 8, wherein the at least one active layer comprises a quantum well.

18. A method for fabricating an optoelectronic device, comprising:

(a) etching one or more first oblique or facetted surfaces on a substrate or template, wherein the first oblique or facetted surfaces are semi-polar planes or non-polar planes; and

(b) forming one or more active layers epitaxially on the first oblique or facetted surfaces or on one or more epitaxial layers formed on the first oblique or facetted surfaces, wherein;

at least one of the active layers includes Indium and has a top surface comprising one or more second oblique or facetted surfaces, and

the second oblique or facetted surfaces are one or more semi-polar planes or one or more non-polar planes;

(c) wherein at least one of the epitaxial layers, substrate, or template, is comprised of (Al, Ga, In)N-based material.

19. The method of claim 18, wherein the surface of the substrate or template is c-plane before the first oblique or facetted surfaces are formed.

20. The method of claim 18, wherein the first oblique or facetted surfaces do not all have the same orientation.

21. The method of claim 18, wherein the first oblique or facetted surfaces have an inclination angle in a range from 25 to 50 degrees.

22. The method of claim 18, wherein the first oblique or facetted surfaces are formed with an inclination angle larger than desired because subsequent layers deposited on the first oblique or facetted surfaces reduce the inclination angle.

23. The method of claim 18, wherein:

(1) the first oblique or facetted surfaces have a maximum depth in a range between 1 nanometer and 10 microns, which determines a surface area of each of the first oblique or facetted surfaces; and

(2) the surface area of each of the first oblique or facetted surfaces has a width in a range between 3 and 10 microns, which determines an angle of inclination of the first oblique or facetted surfaces.

24. The method of claim 18, wherein the first oblique or facetted surfaces are sidewalls or facets of trenches, grooves, or pits in the surface of the substrate or template.

25. A device fabricated using the method of claim 18.

27. The method of claim 18, further comprising forming an etch mask, for the etching, using nanoimprinting.

28. The method of claim 18, further comprising forming electrical contacts such that current is confined to areas of the second oblique or facetted surfaces with a desired inclination angle.

26. A method for fabricating an optoelectronic device, comprising:

(a) performing a lateral overgrowth and forming one or more first oblique or facetted surfaces on a substrate or template, wherein;

the first oblique or facetted surfaces are semi-polar planes or non-polar planes, and

the first oblique or facetted surfaces are surfaces of the lateral overgrowth; and

(b) forming one or more active layers epitaxially on the first oblique or facetted surfaces or on one or more epitaxial layers formed on the first oblique or facetted surfaces, wherein;

at least one of the active layers includes indium and has a top surface comprising one or more second oblique or facetted surfaces, and

the second oblique or facetted surfaces are one or more semi-polar planes or one or more non-polar planes;

(c) wherein at least one of the epitaxial layers, substrate, or template, is comprised of (Al, Ga, In)N-based material.