POLYCRYSTALLINE GALLIUM-NITRIDE SELF-SUPPORTING SUBSTRATE AND LIGHT-EMITTING ELEMENT USING SAME

摘要

Provided is a self-supporting polycrystalline GaN substrate composed of GaN-based single crystal grains having a specific crystal orientation in a direction approximately normal to the substrate. The crystal orientations of individual GaN-based single crystal grains as determined from inverse pole figure mapping by EBSD analysis on the substrate surface are distributed with tilt angles from the specific crystal orientation, the average tilt angle being 1 to 10°. There is also provided a light emitting device including the self-supporting substrate and a light emitting functional layer, which has at least one layer composed of semiconductor single crystal grains, the at least one layer having a single crystal structure in the direction approximately normal to the substrate. The present invention makes it possible to provide a self-supporting polycrystalline GaN substrate having a reduced defect density at the substrate surface, and to provide a light emitting device having a high luminous efficiency.

主权项

1. A self-supporting polycrystalline gallium nitride substrate composed of a plurality of gallium nitride-based single crystal grains having a specific crystal orientation in a direction approximately normal to the substrate,
wherein crystal orientations of individual gallium nitride-based single crystal grains as determined from inverse pole figure mapping by electron backscatter diffraction (EBSD) analysis performed on a substrate surface are distributed with various tilt angles from the specific crystal orientation, wherein an average tilt angle thereof is 1 to 10°, and wherein an aspect ratio T/DT, which is defined as a ratio of a thickness T of the self-supporting polycrystalline gallium nitride substrate to a cross-sectional average diameter DT at an outermost surface of the gallium nitride-based single crystal grains exposed at a top surface of the self-supporting polycrystalline gallium nitride substrate, is preferably 0.7 or greater.