Gallium nitride substrate and manufacturing method of nitride semiconductor crystal
The main purpose of the present invention is to provide: a nonpolar or semipolar GaN substrate, in which a nitride semiconductor crystal having a low stacking fault density can be epitaxially grown on the main surface of the substrate, and a technique required for the production of the substrate. This invention provides: a method for manufacturing an M-plane GaN substrate comprising; forming a mask pattern having a line-shaped opening parallel to an a-axis of a C-plane GaN substrate on an N-polar plane of the C-plane GaN substrate, growing a plane-shape GaN crystal of which thickness direction is an m-axis direction from the opening of the mask pattern by an ammonotharmal method, and cutting out the M-plane GaN substrate from the plane-shape GaN crystal.
1. A gallium nitride substrate comprising a first main surface and a second main surface opposite thereto, the first main surface having a normal vector of which angle to the <10-10> direction is from 0 to 10°, wherein:
the substrate comprises GaN crystal grown by HVPE method,
the substrate has an n-type carrier density of 3×10 18 cm −3 or more, and
a stacking fault density in the first main surface is 50 cm −1 or less as evaluated by a low temperature cathode luminescence method.
2. The gallium nitride substrate according to claim 1 , wherein the stacking fault density is 10 cm −1 or less.
3. The gallium nitride substrate according to claim 1 , wherein the n-type carrier density is 4×10 18 cm −3 or more.
4. The gallium nitride substrate according to claim 1 , wherein the n-type carrier density is 5×10 18 cm −3 or more.
5. The gallium nitride substrate according to claim 1 , wherein a variation of oxygen concentration in a plane parallel to the first main surface is less than five-fold.
6. The gallium nitride substrate according to claim 1 , wherein an oxygen concentration is 4×10 18 cm −3 or more.
7. The gallium nitride substrate according to claim 1 , wherein an angle between a growth direction of a gallium nitride crystal constituting the substrate and the <10-10> direction of the crystal is from 0 to 10°.
8. A gallium nitride substrate comprising a first main surface and a second main surface opposite thereto, the first main surface having a normal vector of which angle to the <10-10> direction is from 0 to 10°, wherein:
the substrate comprises GaN crystal grown by HYPE method,
the substrate has an oxygen concentration is of 4×10 18 cm −3 or more, and
a stacking fault density in the first main surface is 50 cm −1 or less as evaluated by a low temperature cathode luminescence method.
9. The gallium nitride substrate according to claim 8 , wherein the stacking fault density is 10 cm −1 or less.
10. The gallium nitride substrate according to claim 8 , wherein a variation of oxygen concentration in a plane parallel to the first main surface is less than five-fold.
11. The gallium nitride substrate according to claim 8 , wherein the n-type carrier density is 4×10 18 cm −3 or more.
12. The gallium nitride substrate according to claim 8 , wherein the n-type carrier density is 5×10 18 cm −3 or more.
13. The gallium nitride substrate according to claim 8 , wherein an angle between a growth direction of a gallium nitride crystal constituting the substrate and the <10-10> direction of the crystal is from 0 to 10°.
14. A method for manufacturing a semiconductor device, comprising epitaxially growing a nitride semiconductor on the gallium nitride substrate according to claim 1 .
15. The method according to claim 14 , wherein the semiconductor device is a semiconductor light-emitting device.
16. A method for manufacturing a semiconductor device, comprising epitaxially growing a nitride semiconductor on the gallium nitride substrate according to claim 8 .
17. The manufacturing method according to claim 16 , wherein the semiconductor device is a semiconductor light-emitting device.