Group III nitride wafers and fabrication method and testing method

Patent metadata

Field	Value
Publication number	US-10024809-B2
Application number	US-201514806632-A
Country	US
Kind code	B2
Filing date	Jul 22, 2015
Priority date	Apr 7, 2006
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

The invention provides, in one instance, a group III nitride wafer sliced from a group III nitride ingot, polished to remove the surface damage layer and tested with x-ray diffraction. The x-ray incident beam is irradiated at an angle less than 15 degree and diffraction peak intensity is evaluated. The group III nitride wafer passing this test has sufficient surface quality for device fabrication. The invention also provides, in one instance, a method of producing group III nitride wafer by slicing a group III nitride ingot, polishing at least one surface of the wafer, and testing the surface quality with x-ray diffraction having an incident beam angle less than 15 degree to the surface. The invention also provides, in an instance, a test method for testing the surface quality of group III nitride wafers using x-ray diffraction having an incident beam angle less than 15 degree to the surface.

First claim

What is claimed is:

1. A method of fabricating a wafer of group III nitride comprising (a) growing a bulk crystal of group III nitride, (b) slicing the bulk crystal into wafers, (c) polishing at least one surface of a wafer selected from said wafers, and (d) directing an X-ray beam to said surface at an angle of less than 15 degrees to the surface to verify the presence of at least one X-ray diffraction peak, wherein the wafer has a surface either oriented with c-plane or misoriented from the c-plane, wherein said surface misorientation is within +/−10 degrees, and wherein the X-ray diffraction is from 114 plane of the group III nitride crystal.

2. A method according to claim 1 , further comprising a step to compare the intensity of the X-ray diffraction peak with another X-ray diffraction intensity measured with an incident X-ray beam directed to the said surface at an angle of 15 degrees or higher.

3. A method according to claim 2 , wherein the group III nitride comprises gallium nitride.

4. A method according to claim 1 , wherein the step of polishing comprises polishing using a diamond slurry.

5. A method according to claim 4 , wherein the group III nitride comprises gallium nitride.

6. A method according to claim 1 , wherein the step of polishing comprises polishing using colloidal silica.

7. A method according to claim 6 , wherein all of said wafers exhibit said X-ray diffraction peak.

8. A method according to claim 7 , wherein the group III nitride comprises gallium nitride.

9. A method according to claim 6 , wherein the group III nitride comprises gallium nitride.

10. A method according to claim 1 , wherein the peak intensity of the diffraction peak from 114 plane is more than 1/100 of the peak intensity of the diffraction peak from 002 plane.

11. A method according to claim 10 , wherein the group III nitride comprises gallium nitride.

12. A method according to claim 1 , wherein all of said wafers exhibit said X-ray diffraction peak.

13. A method according to claim 12 , and further comprising verifying that the peak intensity of the diffraction peak from 114 plane is more than 1/100 of the peak intensity of the diffraction peak from 002 plane.

14. A method according to claim 13 , wherein the group III nitride comprises gallium nitride.

15. A method according to claim 12 , wherein the group III nitride comprises gallium nitride.

16. A method according to claim 1 wherein said method further comprises additional polishing subsequent to step (d) in the absence of said X-ray diffraction peak.

17. A method according to claim 16 , wherein the group III nitride comprises gallium nitride.

18. A method according to claim 1 , wherein the group III nitride comprises gallium nitride.

Assignees

• Sixpoint Mat Inc
• Seoul Semiconductor Co Ltd

Inventors

• Hashimoto Tadao

Classifications

• H10P90/12

  Preparing bulk and homogeneous wafers · CPC title

• H10P74/203 Primary

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P54/00

  Cutting or separating of wafers, substrates or parts of devices · CPC title

• H10P52/402

  of semiconductor materials · CPC title

• C30B33/06

  Joining of crystals · CPC title