Non-polar a-plane gallium nitride thin films grown by metalorganic chemical vapor deposition

• US 20030198837A1
• Filed: 04/15/2003
• Published: 10/23/2003
• Est. Priority Date: 04/15/2002
• Status: Abandoned Application

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Speck, James Stephen, Craven, Michael D.
• Application Number:
  US10/413,691
• Publication Number:
  US 20030198837A1
• Time in Patent Office: Days
• US Class Current: 428/698
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 25/04 Pattern deposit, e.g. by using masks
• CPC Class Codes: C30B 25/105 by irradiation or electric discharge
• CPC Class Codes: C30B 25/18 characterised by the substrate
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: C30B 29/605 Products containing multiple oriented crystallites, e.g. columnar crystallites
• 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 21/0254 Nitrides
• CPC Class Codes: H01L 21/02609 Crystal orientation
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 21/02647 Lateral overgrowth

Abstract

Non-polar (11{overscore (2)}0) a-plane gallium nitride (GaN) films with planar surfaces are grown on (1{overscore (1)}02) r-plane sapphire substrates by employing a low temperature nucleation layer as a buffer layer prior to a high temperature growth of the non-polar (11{overscore (2)}0) a-plane GaN thin films.

Claims

1. A method of growing a non-polar a-plane gallium nitride thin film on an r-plane substrate through metalorganic chemical vapor deposition, comprising:

(a) annealing the substrate;

(b) depositing a nitride-based nucleation layer on the substrate;

(c) growing the non-polar a-plane gallium nitride film on the nucleation layer; and

(d) cooling the non-polar a-plane gallium nitride film under a nitrogen overpressure.

2. The method of claim 1, wherein the substrate is an r-plane sapphire substrate.

3. The method of claim 2, wherein an in-plane orientation of the gallium nitride film with respect to the r-plane substrate is [0001_]GaN∥

[{overscore (1)}101]_sapphire and [{overscore (1)}100]_GaN∥

[11{overscore (2)}0]_sapphire.

4. The method of claim 1, wherein the substrate is selected from a group comprising silicon carbide, gallium nitride, silicon, zinc oxide, boron nitride, lithium aluminate, lithium niobate, germanium, aluminum nitride, and lithium gallate.

5. The method of claim 1, wherein the annealing step (a) comprises a high temperature annealing of the substrate.

6. The method of claim 1, wherein the depositing step (b) comprises a low temperature deposit of the nitride-based nucleation layer on the substrate.

7. The method of claim 1, wherein the depositing step (b) comprises a low pressure deposit of the nitride-based nucleation layer on the substrate.

8. The method of claim 1, wherein the low temperature depositing conditions comprise approximately 400-900°

C. and atmospheric pressure.

9. The method of claim 1, wherein the depositing step (b) initiates gallium nitride growth on the r-plane substrate.

10. The method of claim 1, wherein the nucleation layer comprises 1-100 nanometers of gallium nitride.

11. The method of claim 1, wherein the growing step (b) comprises a high temperature growth of the non-polar a-plane gallium nitride film on the nucleation layer.

12. The method of claim 11, wherein the high temperature layer is deposited at 0.2 atmospheres or less.

13. The method of claim 11, wherein the high temperature growth conditions comprise approximately 1100°

C. growth temperature, approximately 0.2 atmosphere or less growth pressure, 30 μ

mol per minute gallium flow, and 40,000 μ

mol per minute nitrogen flow.

14. The method of claim 1, wherein the growing step (b) produces the planar gallium nitride film.

15. A device manufactured using the method of claim 1.

16. A non-polar a-plane gallium nitride thin film on an r-plane substrate, wherein the thin film is created using a process comprising:

(a) annealing the substrate;

(b) depositing a nitride-based nucleation layer on the substrate;

(c) growing the non-polar a-plane gallium nitride film on the nucleation layer; and

(d) cooling the non-polar a-plane gallium nitride film under a nitrogen overpressure.

17. The thin film of claim 16, wherein the substrate is an r-plane sapphire substrate.

18. The thin film of claim 17, wherein an in-plane orientation of the gallium nitride films with respect to the r-plane substrate is [0001]_GaN∥

[{overscore (1)}101]_sapphire and [{overscore (1)}100]_GaN∥

[11{overscore (2)}0]_sapphire.

19. The thin film of claim 16, wherein the substrate is selected from a group comprising silicon carbide, gallium nitride, silicon, zinc oxide, boron nitride, lithium aluminate, lithium niobate, germanium, aluminum nitride, and lithium gallate.

20. The thin film of claim 16, wherein the annealing step (a) comprises a high temperature annealing of the substrate.

21. The thin film of claim 16, wherein the depositing step (b) comprises a low temperature deposit of the nitride-based nucleation layer on the substrate.

22. The thin film of claim 16, wherein the depositing step (b) comprises a low pressure deposit of the nitride-based nucleation layer on the substrate.

23. The thin film of claim 16, wherein the low temperature depositing conditions comprise approximately 400-900°

C. and atmospheric pressure.

24. The thin film of claim 16, wherein the depositing step (b) initiates gallium nitride growth on the r-plane substrate.

25. The thin film of claim 16, wherein the nucleation layer comprises 1-100 nanometers of gallium nitride.

26. The thin film of claim 16, wherein the growing step (b) comprises a high temperature growth of the non-polar a-plane gallium nitride films on the nucleation layer.

27. The thin film of claim 26, wherein the high temperature layer is deposited at 0.2 atmospheres or less.

28. The thin film of claim 26, wherein the high temperature growth conditions comprise approximately 1100°

C. growth temperature, approximately 0.2 atmosphere or less growth pressure, 30 μ

mol per minute gallium flow, and 40,000 μ

mol per minute nitrogen flow.

29. The thin film of claim 16, wherein the growing step (b) produces a planar gallium nitride film.

30. A structure having a non-polar a-plane gallium nitride thin film on an r-plane substrate, comprising:

(a) an annealed substrate;

(b) a nitride-based nucleation layer deposited on the substrate; and

(c) a non-polar a-plane gallium nitride film grown on the nucleation layer and cooled under a nitrogen overpressure.

31. The structure of claim 30, wherein the substrate is an r-plane sapphire substrate.

32. The structure of claim 31, wherein an in-plane orientation of the gallium nitride film with respect to the r-plane substrate is [0001]_GaN∥

[{overscore (1)}101]_sapphire and [{overscore (1)}100]_GaN∥

[11{overscore (2)}0]_sapphire.

33. The structure of claim 30, wherein the substrate is selected from a group comprising silicon carbide, gallium nitride, silicon, zinc oxide, boron nitride, lithium aluminate, lithium niobate, germanium, aluminum nitride, and lithium gallate.