Free-standing gallium nitride semiconductor substrate useful in light emitting device, comprises free standing compound semiconductor crystal based on nitride

摘要

The free-standing gallium nitride semiconductor substrate useful in light emitting device, comprises free standing compound semiconductor crystal based on nitride, which has a variation of the lattice constant of +-12 ppm. The variation of the lattice constant comprises a variation of the measured a-axis-length and a variation of the total measured lattice constant in the level of an area with exception of a part outwardly reaching from an extreme circumference in a direction of substrate radius of 2 mm. An independent claim is included for a light- emitting device.