Abstract: A method of manufacturing a gallium nitride single-crystal substrate includes a step of grinding a main surface by arranging a grindstone and a gallium nitride single crystal having a semipolar plane or a nonpolar plane as the main surface to face each other and pressing the grindstone and the gallium nitride single crystal against each other while moving the grindstone and the gallium nitride single crystal relative to each other. The main surface is ground to make an angle formed by a direction in which the grindstone grinds the main surface and a direction obtained by projecting a c-axis of the gallium nitride single crystal onto the main surface within at least one range selected from (A)-45° or more and 45° or less; (B) 55° or more and 135° or less; and (C) ?135° or more and ?55° or less.

Abstract: A method of manufacturing a gallium nitride single-crystal substrate includes a step of grinding a main surface by arranging a grindstone and a gallium nitride single crystal having a semipolar plane or a nonpolar plane as the main surface to face each other and pressing the grindstone and the gallium nitride single crystal against each other while moving the grindstone and the gallium nitride single crystal relative to each other. The main surface is ground to make an angle formed by a direction in which the grindstone grinds the main surface and a direction obtained by projecting a c-axis of the gallium nitride single crystal onto the main surface be within at least one range selected from the group consisting of ranges A, C, and E below.