Sapphire substrate having triangular projections with portions extending in direction of substrate crystal axis

摘要

The sapphire substrate has a principal surface for growing a nitride semiconductor to form a nitride semiconductor light emitting device and comprising a plurality of projections of the principal surface, wherein an outer periphery of a bottom surface of each of the projections has at least one depression. This depression is in the horizontal direction. The plurality of projections are arranged so that a straight line passes through the inside of at least any one of projections when the straight line is drawn at any position in any direction in a plane including the bottom surfaces of the plurality of projections.

主权项

1. A sapphire substrate having a principal surface for growing a nitride semiconductor to form a nitride semiconductor light emitting device, the sapphire substrate comprising a plurality of projections on the principal surface,
wherein each projection of the plurality of projections is separated from each adjacent projection of the plurality of projections, wherein each of the projections has a bottom that has a substantially triangular shape, wherein each side of the bottom of the projections has a depression in its center, wherein extended portions of the bottoms of the respective projections extend in a direction that is within a range of ±10 degrees of a crystal axis “a” of the sapphire substrate, and wherein the plurality of projections are arranged so that any straight line that is drawn at any position in any direction in a plane including the bottoms of the plurality of projections passes through a geometric area of the bottom of at least one of projections.