Miscut semipolar optoelectronic device

• US 8,368,179 B2
• Filed: 12/06/2011
• Issued: 02/05/2013
• Est. Priority Date: 01/20/2006
• Status: Active Grant

• Current Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan), Regents of the University of California (University of California)
• Original Assignee: Japan Science & Technology Trading Co. Limited, Regents of the University of California (University of California)
• Inventors: Kaeding, John F., Lee, Dong-Seon, Iza, Michael, Baker, Troy J., Sato, Hitoshi, Haskell, Benjamin A., Speck, James S., DenBaars, Steven P., Nakamura, Shuji
• Primary Examiner(s): Chang, Leonard
• Application Number:
  US13/311,986
• Publication Number:
  US 20120074525A1
• Time in Patent Office: 427 Days
• Field of Search: 438/22, 438/46, 438/478, 438/503, 257/615, 257/631, 257/E29.089
• US Class Current: 257/615
• CPC Class Codes: C30B 23/025 characterised by the substrate
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 25/18 characterised by the substrate
• CPC Class Codes: C30B 25/183 being provided with a buffer layer, e.g. a lattice matching layer
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: H01L 21/02378 Silicon carbide
• 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 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 33/007 comprising nitride compounds

Abstract

A method for improved growth of a semipolar (Al,In,Ga,B)N semiconductor thin film using an intentionally miscut substrate. Specifically, the method comprises intentionally miscutting a substrate, loading a substrate into a reactor, heating the substrate under a flow of nitrogen and/or hydrogen and/or ammonia, depositing an In_xGa_1-xN nucleation layer on the heated substrate, depositing a semipolar nitride semiconductor thin film on the In_xGa_1-xN nucleation layer, and cooling the substrate under a nitrogen overpressure.

Claims

1. A crystal, comprising (Al,In,Ga,B)N or III-nitride and a surface perpendicular to a growth direction of the crystal, wherein:

the surface is at least 10 micrometers wide,

the surface has a semi-polar orientation, and

the crystal has a crystalline quality characterized by a rocking curve having a full width at half maximum (FWHM) of less than 0.55 degrees as measured by X-ray Diffraction.

2. The crystal of claim 1, wherein the FWHM is less than 900 arcseconds.

3. The crystal of claim 1, wherein the surface is planar.

4. The crystal of claim 1, wherein the surface is a largest surface of the crystal.

5. The crystal of claim 1, further comprising a semi-polar III-nitride light emitting diode fabricated on the surface that emits light with an output power of more than 220 microwatts.

6. The crystal of claim 1, wherein the crystal contains a single crystallographic domain.

7. The crystal of claim 1, wherein:

the crystal is on a miscut surface of a substrate, and the surface is oppisite a side of the crystal adjacent to the miscut surface.

8. The crystal of claim 7, wherein the miscut surface of the substrate is miscut away from a low index crystal orientation of the substrate.

9. The crystal of claim 8, wherein:

the miscut surface is oriented at a miscut angle with respect to a primary crystal orientation of the substrate, and

the miscut angle is between 0.5°

-20°

.

10. The crystal of claim 8, wherein the miscut angle is between 0.5°

-3°

.

11. The crystal of claim 7, wherein the crystal is deposited heteroepitaxially on the substrate.

12. The crystal of claim 11, wherein:

the semi-polar orientation is {10-11},

the substrate is a {100} MgAl₂O₄ spinel substrate, and

the miscut surface is oriented at a miscut angle with respect to the {100} orientation of the spinel substrate and in a <

011>

direction.

13. The initial crystal of claim 11, wherein:

the semi-polar orientation is {11-22},

the substrate is a {1-100} Al₂O₃ sapphire substrate, and

the miscut surface is oriented at a miscut angle with respect to the {1-100} orientation of the sapphire substrate and in a <

0001>

direction.

14. The crystal of claim 7, wherein the substrate is Gallium Nitride (GaN).

15. The crystal of claim 7, wherein the substrate is sapphire.

16. The crystal of claim 7, wherein the substrate is spinel.

17. The crystal of claim 7, wherein the substrate is silicon carbide.

18. The crystal of claim 7, wherein the substrate is aluminum nitride.

19. The film of claim 7, wherein:

the crystal has a reduced defect density, and

the surface is smoother,

as compared to an (Al,In,Ga,B)N or III-nitride crystal deposited on a surface of the substrate that is different from the miscut surface.

20. The crystal of claim 7, wherein the crystal is part of a III-nitride light emitting device having a brighter emission than a similar device fabricated on a surface of the substrate that is different from the miscut surface.

21. The crystal of claim 1, wherein the crystal is part of a light emitting device comprising InN, AlGaN, InGaN, or AlInN.

22. The crystal of claim 7, wherein the miscut surface is an intentionally miscut surface.

23. The crystal of claim 1, wherein the semi-polar orientation is {11-22}.

24. The crystal of claim 1, wherein the semi-polar orientation is {10-11}.

25. The crystal of claim 1, wherein the semi-polar orientation is {10-12}.

26. The crystal of claim 1, wherein the semi-polar orientation is {10-13}.

27. The crystal of claim 1, wherein the crystal is Gallium Nitride (GaN).

28. The crystal of claim 1, wherein the is Aluminum Nitride.

29. The crystal of claim 1, wherein the surface has an area of more than 4 millimeters by 10 millimeters.

30. A device structure, comprising:

A semi-polar crystal comprising (Al,In,Ga,B)N or III-nitride, wherein;

the semi-polar crystal is grown on a miscut surface of a substrate,

a subsequent semi-polar III-nitride or (Al,In,Ga,B)N layer is grown on a top surface of the semi-polar crystal,

the top surface is a grown surface opposite a side of the crystal adjacent the miscut surface of the substrate, and

the semi-polar crystal has a crystalline quality characterized by a rocking curve having a full width at half maximum (FWHM) of less than 0.55 degrees as measured by X-ray Diffraction.

31. A method of fabricating a III-nitride crystal, comprising:

depositing a crystal on a miscut surface of a substrate, wherein;

the crystal comprises (Al,In,Ga,B)N or III-nitride and a surface perpendicular to a growth direction of the crystal,

the surface is at least 10 micrometers wide,

the surface has a semi-polar orientation, and

the crystal has a crystalline quality characterized by a rocking curve having a full width at half maximum (FWHM) of less than 0.55 degrees as measured by X-ray Diffraction.

32. The method of claim 31, wherein:

the depositing is by Metal Organic Chemical Vapor Deposition or Hydride Vapor Phase Epitaxy,

a deposition pressure is between 10 torr and 1000 torr, and

a deposition temperature is between 400°

C. and 1400°

C.

33. The method of claim 32, wherein the depositing uses a flow comprising at least one of nitrogen, hydrogen or ammonia.

34. The method of claim 31, further comprising selecting the miscut surface such that a III-nitride light emitting diode fabricated on the surface emits light with an output power of more than 220 microwatts.

35. The method of claim 31, wherein the miscut surface of the substrate is miscut away from a low index crystal orientation.

36. The method of claim 31, further comprising selecting the miscut surface wherein:

the crystal has a reduced defect density, and

the surface is smoother,

as compared to an (Al,In,Ga,B)N or III-nitride crystal deposited on a surface of the substrate that is different from the miscut surface.

37. The method of claim 31, further comprising selecting the miscut surface wherein the crystal is part of a III-nitride light emitting device having a brighter emission than a similar device fabricated on a surface of the substrate that is different from the miscut surface.

38. The method of claim 31, further comprising polishing, cutting, or polishing and cutting a surface of the substrate to form the miscut surface.

39. The method of claim 31, further comprising depositing a semi-polar III-nitride light emitting diode on the surface, wherein the III-nitride light emitting diode emits light with an output power of more than 220 microwatts.