Polycrystalline gallium nitride free-standing substrate and light emitting device using the same

摘要

Provided is 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. In this self-supporting substrate, the 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 the substrate surface are distributed with various tilt angles from the specific crystal orientation, and the average tilt angle thereof is 1 to 10°. Moreover, the light emitting device of the present invention comprises the foregoing self-supporting substrate and a light emitting functional layer formed on the substrate, wherein the light emitting functional layer has at least one layer composed of a plurality of semiconductor single crystal grains, wherein the at least one layer has a single crystal structure in the direction approximately normal to the substrate. According to the present invention, it is possible to provide a self-supporting polycrystalline gallium nitride substrate having a reduced defect density at the substrate surface. Also, it is possible to provide a light emitting device having a high luminous efficiency by using the self-supporting polycrystalline gallium nitride substrate of the present invention.