Gallium nitride substrate and manufacturing method of nitride semiconductor crystal
View Patent ↗The invention provides 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 method for manufacturing an M-plane GaN substrate by 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 ammonothermal method, and cutting out the M-plane GaN substrate from the plane-shape GaN crystal.
1. 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 ammonothermal method, and
cutting out the M-plane GaN substrate from the plane-shape GaN crystal.
2. A method for manufacturing a GaN substrate having an M-plane or a semi-polar plane as a main surface 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 first GaN crystal of which thickness direction is an m-axis direction from the opening of the mask pattern by an ammonothermal method,
cutting out an M-plane seed substrate from the plane-shape first GaN crystal,
growing a second GaN crystal using the M-plane seed substrate as a seed by an ammonothermal method, and
cutting out the GaN substrate having an M-plane or semi-polar plane as a main surface from the second GaN crystal.
3. The method for manufacturing a GaN substrate according to claim 2 , wherein the semi-polar plane is {30-31}, {30-3-1}, {20-21}, {20-2-1}, {10-11}, or {10-1-1}.
4. The method for manufacturing a GaN substrate according to claim 2 , wherein the area of the main surface is 1.0 cm 2 or more.
5. The method for manufacturing a GaN substrate according to claim 4 , wherein averaged basal plane dislocation density in an optional square region sizing 250 μm×250 μm in the main plane is 1×10 6 cm −2 or less.
6. The method for manufacturing a GaN substrate according to claim 5 , wherein the basal plane dislocation density in the main plane is 1×10 4 cm −2 or less.
7. The method for manufacturing a GaN substrate according to claim 6 , wherein the basal plane dislocation density in the main plane is 1×10 2 cm −2 or less.
8. The method for manufacturing a GaN substrate according to claim 6 , wherein the averaged basal plane dislocation density in the optional square region sizing 250 μm×250 μm in the main plane is 1×10 4 cm −2 or less.
9. The method for manufacturing a GaN substrate according to claim 5 , wherein stacking fault density in the main surface is 10 cm −1 or less.
10. A method for manufacturing a GaN substrate having an M-plane or semi-polar plane as a main surface 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 first GaN crystal of which thickness direction is an m-axis direction from the opening of the mask pattern by an ammonothermal method,
cutting out an M-plane first seed substrate from the plane-shape first GaN crystal,
growing a second GaN crystal using the M-plane first seed substrate as a seed by an ammonothermal method,
cutting out a second seed substrate having an M-plane or semi-polar plane as a main surface from the second GaN crystal,
growing a third GaN crystal using the second seed substrate as a seed by a vapor phase growth method, and
cutting out the GaN substrate having an M-plane or semi-polar plane as a main surface from the third GaN crystal.
11. The method for manufacturing a GaN substrate according to claim 10 , wherein the vapor phase growth method is a HVPE method.
12. The method for manufacturing a GaN substrate according to claim 10 , wherein the main surface of the GaN substrate cut out from the third GaN crystal is {10-10}, {30-31}, {30-3-1}, {20-21}, {20-2-1}, {10-11}, or {10-1-1}.
13. The method for manufacturing a GaN substrate according to claim 10 , wherein the area of the main surface of the second seed substrate is 1.0 cm 2 or more.
14. The method for manufacturing a GaN substrate according to claim 10 , wherein averaged basal plane dislocation density in an optional square region sizing 250 μm×250 μm in the main plane of the second seed substrate is 1×10 6 cm −2 or less.
15. The method for manufacturing a GaN substrate according to claim 14 , wherein the basal plane dislocation density in the main plane of the second seed is 1×10 4 cm −2 or less.
16. The method for manufacturing a GaN substrate according to claim 15 , wherein the basal plane dislocation density in the main plane of the second seed is 1×10 2 cm −2 or less.
17. The method for manufacturing a GaN substrate according to claim 15 , wherein the averaged basal plane dislocation density in an optional square region sizing 250 μm×250 μm in the main plane of the second seed is 1×10 4 cm −2 or less.
18. The method for manufacturing a GaN substrate according to claim 14 , wherein stacking fault density in the main surface of the second seed is 10 cm −1 or less.