Method and surface morphology of non-polar gallium nitride containing substrates

• US 8,524,578 B1
• Filed: 07/13/2012
• Issued: 09/03/2013
• Est. Priority Date: 05/29/2009
• Status: Active Grant

• Current Assignee: SL Technology Incorporated (Reliv' International, Inc.)
• Original Assignee: Soraa, Inc.
• Inventors: Raring, James W., Poblenz, Christiane
• Primary Examiner(s): HA, NATHAN W
• Application Number:
  US13/548,770
• Time in Patent Office: 417 Days
• Field of Search: 257/628, 257/94, 438/478, 438/46, 438/479, 438/958, 372/45.01, 117101-103
• US Class Current: 438/479
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

An optical device, e.g., LED, laser. The device includes a non-polar gallium nitride substrate member having a slightly off-axis non-polar oriented crystalline surface plane. In a specific embodiment, the slightly off-axis non-polar oriented crystalline surface plane is up to about −0.6 degrees in a c-plane direction, but can be others. In a specific embodiment, the present invention provides a gallium nitride containing epitaxial layer formed overlying the slightly off-axis non-polar oriented crystalline surface plane. In a specific embodiment, the device includes a surface region overlying the gallium nitride epitaxial layer that is substantially free of hillocks.

Claims

1. A method of fabricating an optical device, the method comprising:

providing a non-polar (10-10) gallium and nitrogen containing substrate member having a off-axis non-polar oriented crystalline surface plane, the off-axis non-polar oriented crystalline surface plane being greater in magnitude than about negative 0.6 degrees toward the c-plane (0001); and

forming a gallium and nitrogen containing epitaxial layer having a surface region substantially free of hillocks overlying the off-axis non-polar oriented crystalline surface plane.

2. The method of claim 1 wherein the forming comprises using a mixture of hydrogen entities and nitrogen entities as a carrier gas.

3. The method of claim 1 wherein the off axis non-polar oriented crystalline surface plane is greater in magnitude than about negative 0.7 degrees toward (0001).

4. The method of claim 1 wherein the off-axis non-polar oriented crystalline surface plane is greater in magnitude than about negative 0.8 degrees toward (0001).

5. The method of claim 1 wherein the off-axis non-polar oriented crystalline surface plane is greater in magnitude than about negative 0.9 degrees toward (0001).

6. The method of claim 1 wherein the off-axis non-polar oriented crystalline surface plane is greater in magnitude than about negative 1.0 degrees toward (0001).

7. The method of claim 1 wherein the off-axis non-polar oriented crystalline surface plane is greater in magnitude than about negative 1.1 degrees toward (0001).

8. The method of claim 1 wherein the off-axis non-polar oriented crystalline surface plane is greater in magnitude than about negative 1.2 degrees toward (0001).

9. The method of claim 1 further comprising forming an optical device using at least the gallium and nitrogen containing epitaxial layer.

10. A method of fabricating an optical device, the method comprising:

providing a non-polar (10-10) gallium and nitrogen containing substrate member having a off axis non-polar oriented crystalline surface plane, the off-axis non-polar oriented crystalline surface plane ranging from about 0 degrees to a predetermined degree toward either or both the c-plane or a-plane; and

forming a gallium and nitrogen containing epitaxial layer, using at least an atmospheric pressure process, to form a region of a quantum well having a thickness, the gallium and nitrogen containing epitaxial layer having a surface region substantially free from hillocks.

11. The method of claim 10 wherein the forming comprising using a pure nitrogen entity carrier gas.

12. The method of claim 10 further comprising maintaining the non-polar gallium and nitrogen containing substrate member in atmospheric pressure during at least the forming of the gallium and nitrogen containing epitaxial layer.

13. The method of claim 10 wherein the atmospheric pressure ranges from about 700-800 Torr.

14. The method of claim 10 wherein the surface region is substantially free from hillocks ranging from 10-100 microns in dimension.

15. The method of claim 10 wherein the surface region is substantially free from hillocks ranging from 100-200 microns in dimension.

16. The method of claim 10 wherein at least 90% of the area of the surface region is free from hillocks ranging from 10-100 microns in dimension.

17. The method of claim 10 wherein the thickness is at least 3.5 nanometers and greater.