Nitride semiconductor single-crystal substrate and method of its synthesis

摘要

Fracture toughness of AlGaN single-crystal substrate is improved and its absorption coefficient reduced. A nitride semiconductor single-crystal substrate has a composition represented by the formula Al x Ga 1-x N (0 ‰¤ x ‰¤ 1), and is characterized by having a fracture toughness of (1.2-0.7x) MPa€¢m 1/2 or greater and a surface area of 20 cm 2 , or, if the substrate has a composition represented by the formula Al x Ga 1-x N (0.5 ‰¤ x ‰¤ 1), by having an absorption coefficient of 50 cm -1 or less in a 350 to 780 nm total wavelength range.