C-plane GaN substrate

Patent metadata

Field	Value
Publication number	US-10224201-B2
Application number	US-201715675230-A
Country	US
Kind code	B2
Filing date	Aug 11, 2017
Priority date	Feb 23, 2015
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

Provides is a C-plane GaN substrate which, although formed from a GaN crystal grown so that surface pits are generated, is free from any inversion domain, and moreover, has a low spiral dislocation density in a gallium polar surface. Provides is a C-plane GaN substrate wherein: the substrate comprises a plurality of facet growth areas each having a closed ring outline-shape on a gallium polar surface; the spiral dislocation density is less than 1×106 cm−2 anywhere on the gallium polar surface; and the substrate is free from any inversion domain. The C-plane GaN substrate may comprise a high dislocation density part having a dislocation density of more than 1×107 cm−2 and a low dislocation density part having a dislocation density of less than 1×106 cm−2 on the gallium polar surface.

First claim

The invention claimed is:

1. A C-plane GaN substrate comprising:
a plurality of facet growth areas each having a closed ring outline-shape on a gallium polar surface, wherein
a spiral dislocation density is less than 1×10 6 cm −2 anywhere on the gallium polar surface, and
the gallium polar surface is free from any inversion domain.

2. The C-plane GaN substrate according to claim 1 , wherein the spiral dislocation density is less than 8×10 5 cm −2 anywhere on the gallium polar surface.

3. The C-plane GaN substrate according to claim 1 , wherein the substrate comprises a high dislocation density part having a dislocation density of more than 1×10 7 cm −2 and a low dislocation density part having a dislocation density of less than 1×10 6 cm −2 on the gallium polar surface.

4. The C-plane GaN substrate according to claim 3 , wherein, when the entire gallium polar surface is comparted into 100-μm square compartments, 1% or more of all the compartments each have a dislocation density of less than 1×10 5 cm −2 .

5. The C-plane GaN substrate according to claim 1 , wherein the substrate is doped with oxygen.

6. The C-plane GaN substrate according to claim 1 , wherein the substrate is doped with either or both of silicon and germanium.

7. The C-plane GaN substrate according to claim 1 , wherein the substrate has an electrical resistivity of 0.1 Ω·cm or less.

8. The C-plane GaN substrate according to claim 1 , wherein the plurality of facet growth areas are at least partially regularly arranged on the main surface.

9. A method for producing a nitride semiconductor device, comprising a step of preparing the C-plane GaN substrate according to claim 1 , and a step of epitaxially growing at least one nitride semiconductor layer on the prepared C-plane GaN substrate.

10. A method for producing an epitaxial wafer, comprising a step of preparing the C-plane GaN substrate according to claim 1 , and a step of epitaxially growing at least one nitride semiconductor layer on the prepared C-plane GaN substrate.

11. A C-plane GaN substrate having a gallium polar surface, the substrate comprising:
a plurality of facet growth areas each having a closed ring outline-shape on the gallium polar surface, wherein
when a virtual square grid of 2 cm×2 cm is drawn on the gallium polar surface, each cell of the grid comprises at least one 1 cm×1 cm square area in which a spiral dislocation density is anywhere less than 1×10 6 cm −2 , and
the gallium polar surface is free from any inversion domain.

12. The C-plane GaN substrate according to claim 11 , wherein each cell of the grid comprises at least one 1 cm×1 cm square area in which a spiral dislocation density is anywhere less than 8×10 5 cm −2 .

13. The C-plane GaN substrate according to claim 11 , wherein the substrate comprises a high dislocation density part having a dislocation density of more than 1×10 7 cm −2 and a low dislocation density area having a dislocation density of less than 1×10 6 cm −2 on the gallium polar surface.

14. The C-plane GaN substrate according to claim 13 , wherein, when the entire gallium polar surface is comparted into compartments of 100 μm-square, 1% or more of all the compartments each have a dislocation density of less than 1×10 5 cm −2 .

15. The C-plane GaN substrate according to claim 11 , wherein the substrate is doped with oxygen.

16. The C-plane GaN substrate according to claim 11 , wherein the substrate is doped with either or both of silicon and germanium.

17. The C-plane GaN substrate according to claim 11 , wherein the substrate has an electrical resistivity of 0.1 Ω·cm or less.

18. The C-plane GaN substrate according to claim 11 , wherein the plurality of facet growth areas are at least partially regularly arranged on the main surface.

19. A method for producing a nitride semiconductor device, comprising a step of preparing the C-plane GaN substrate according to claim 11 , and a step of epitaxially growing at least one nitride semiconductor layer on the prepared C-plane GaN substrate.

20. A method for producing an epitaxial wafer, comprising a step of preparing the C-plane GaN substrate according to claim 11 , and a step of epitaxially growing at least one nitride semiconductor layer on the prepared C-plane GaN substrate.

Assignees

• Mitsubishi Chem Corp

Inventors

• Iso Kenji
• Enatsu Yuuki
• Kimura Hiromitsu

Classifications

• H10P14/3466

  Crystal orientation · CPC title

• H10P14/3442

  N-type · CPC title

• H10P14/3438

  Doping during depositing · CPC title

• H10P14/3416

  Nitrides · CPC title

• H10P14/276

  Lateral overgrowth · CPC title