Gallium nitride substrate and manufacturing method of nitride semiconductor crystal

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 ammonotharmal 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 ammonotharmal method, and
• cutting out the GaN substrate having an M-plane or semi-polar plane as a main surface from the second GaN crystal.

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 ammonotharmal 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 ammonotharmal 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.