Gallium nitride crystal, group 13 nitride crystal, group 13 nitride crystal substrate, and manufacturing method

Patent metadata

Field	Value
Publication number	US-9863058-B2
Application number	US-201514708583-A
Country	US
Kind code	B2
Filing date	May 11, 2015
Priority date	Sep 14, 2011
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A gallium nitride crystal having a hexagonal crystal structure includes a first region located on an inner side of a cross section intersecting c-axis of the hexagonal crystal structure, and a second region surrounding at least a part of the outer periphery of the first region in the cross section. An emission spectrum of each of the first region and the second region with electron beam or ultraviolet light excitation has a first peak including a band edge emission of gallium nitride and a second peak located in a longer wavelength area than the first peak. A peak intensity of the first peak is smaller than a peak intensity of the second peak in the first region, and a peak intensity of the first peak is greater than a peak intensity of the second peak in the second region.

First claim

What is claimed is:

1. A gallium nitride crystal having a hexagonal crystal structure comprising:
a first region located on an inner side of a cross section intersecting c-axis of the hexagonal crystal structure; and
a second region surrounding at least a part of the outer periphery of the first region in the cross section, wherein
an emission spectrum of each of the first region and the second region with electron beam or ultraviolet light excitation has a first peak including a band edge emission of gallium nitride and a second peak located in a longer wavelength area than the first peak,
a peak intensity of the first peak is smaller than a peak intensity of the second peak in the first region, and
a peak intensity of the first peak is greater than a peak intensity of the second peak in the second region.

2. The gallium nitride crystal according to claim 1 , wherein
the emission spectrum is measured at a room temperature, and
the second peak is located in a wavelength range of 450 nm to 650 nm.

3. The gallium nitride crystal according to claim 2 , wherein
the second peak is located in a wavelength range of 590 nm to 650 nm.

4. The gallium nitride crystal according to claim 1 , wherein
the second region surrounds an entire outer periphery of the first region in the cross section.

5. The gallium nitride crystal according to claim 1 , wherein
a thickness of the second region is 100 nm or more in the cross section.

6. The gallium nitride crystal according to claim 1 , wherein
a boron density of the first region is higher than the boron density of the second region.

7. The gallium nitride crystal according to claim 6 , wherein
the boron density of the first region is 4×10 18 atms/cm 3 or more, and
the boron density of the second region is less than 4×10 18 atms/cm 3 .

8. The gallium nitride crystal according to claim 1 , wherein
a length L in a c-axis direction is 9.7 mm or more, and a ratio L/d which is a ratio of the length L to a crystal diameter din c-plane is larger than 0.813.

9. The gallium nitride crystal according to claim 8 , wherein
the length L is 37.4 mm or more.

10. A group 13 nitride crystal containing therein at least a part of the gallium nitride crystal according to claim 1 .

11. The gallium nitride crystal according to claim 10 , wherein
a dislocation density of a region other than the gallium nitride crystal in c-plane of the group 13 nitride crystal is smaller than the dislocation density of the gallium nitride crystal contained in the c-plane on an inner side of the group 13 nitride crystal.

12. A group 13 nitride crystal substrate containing at least a part of the gallium nitride crystal according to claim 1 .

13. The group 13 nitride crystal substrate according to claim 12 , wherein a c-plane of the hexagonal crystal structure is a main surface.

Assignees

• Hayashi Masahiro
• Sarayama Seiji
• Satoh Takashi
• Nambu Hiroshi
• Kimura Chiharu
• Miyoshi Naoya
• Ricoh Co Ltd

Inventors

• Hayashi Masahiro
• Sarayama Seiji
• Satoh Takashi
• Nambu Hiroshi
• Kimura Chiharu
• Miyoshi Naoya

Classifications

• C30B9/12 Primary

  Salt solvents, e.g. flux growth · CPC title

• C30B29/406

  Gallium nitride · CPC title

• Y10T428/26

  Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension · CPC title

• Y10T428/239

  Complete cover or casing · CPC title