Mitsubishi Chemical Corporation

Yasuhiro Uchiyama

Kenji Fujito

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 Z1&#x3e;0 expression (1), wherein Z1 (&#x3bc;m) is an amount of warpage of physical shape in a growth surface of the single-crystal substrate and Z2&#x3c;0 expression (2), wherein Z2 (&#x3bc;m) is an amount of warpage calculated from a radius of curvature of crystallographic-plane shape in a growth surface of the single-crystal substrate.

Process for producing a group-III nitride crystal and process for producing a light-emitting semiconductor element or a semiconductor device comprising a group-III nitride crystal

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 (&#x3bc;m) is an amount of warpage of physical shape in a growth surface of the single-crystal substrate and Z2 (&#x3bc;m) is an amount of warpage calculated from a radius of curvature of crystallographic-plane shape in a growth surface of the single-crystal substrate: &#x2212;40&#x3c;Z2/Z1&#x3c;&#x2212;1: Expression (1).

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Ushiku, Japan

Yasuhiro Uchiyama