Epitaxial substrate for semiconductor device, schottky junction structure, and leakage current suppression method for schottky junction structure

摘要

Provided is an epitaxial substrate (10) for semiconductor device that is capable of achieving a semiconductor device having high reliability in reverse characteristics of schottky junction. An epitaxial substrate (10) for semiconductor device obtained by forming, on a base substrate (1), a group of group III nitride layers by lamination such that a (0001) crystal plane of each layer is approximately parallel to a substrate surface includes: a channel layer (3) formed of a first group III nitride having a composition of In x1 Al y1 Ga z1 N (x1+y1+z1=1, z1>0); and a barrier layer (5) formed of a second group III nitride having a composition of In x2 Al y2 N (x2+y2=1, x2>0, y2>0), wherein the second group III nitride is a short-range-ordered mixed crystal having a short-range order parameter ± satisfying a range where 0<±<1.