SINGLE-CRYSTAL SUBSTRATE, GROUP III ELEMENT NITRIDE CRYSTAL OBTAINED USING SAME, AND PROCESS FOR PRODUICNG GROUP III ELEMENT NITRIDE CRYSTAL

摘要

Provided is a base substrate with which a Group-III nitride crystal having a large area and a large thickness can be grown while inhibiting crack generation. A single-crystal substrate for use in growing a Group-III nitride crystal thereon, which satisfies the following expression (1), wherein Z1 (µm) is an amount of warpage of physical shape in a growth surface of the single-crystal substrate and Z2 (µm) is an amount of warpage calculated from a radius of curvature of crystallographic-plane shape in a growth surface of the single-crystal substrate: -40Z2/Z1-1 : Expression (1).