Nitride semiconductor epitaxial substrate and nitride semiconductor device

摘要

There is provided a nitride semiconductor epitaxial substrate having a group III nitride semiconductor layer with C-plane as a surface, grown on a substrate via a buffer layer of the group III nitride semiconductor containing Al, wherein the buffer layer has an inversion domain on the surface.

主权项

1. A nitride semiconductor epitaxial substrate, comprising:
a buffer layer grown on a substrate, composed of a group III nitride semiconductor containing Al, and having a thickness between 10-300 nm; and a group III nitride semiconductor layer grown on the buffer layer, wherein in a surface of the buffer layer an inversion domain having N-polar is irregularly distributed, and the group III nitride semiconductor layer is configured so that a layer grown on the inversion domain on the surface of the buffer layer is embedded by a layer grown on a region other than the inversion domain on the surface of the buffer layer, an inversion domain does not exist on a surface of the group III nitride semiconductor layer, the surface of the group III nitride semiconductor layer is a C-plane of group III polarity, a dislocation density on the surface of the group III nitride semiconductor layer is 5×108 cm−2 or less, and the dislocation density on the surface of the group III nitride semiconductor layer is lower than a dislocation density of a region in which the inversion domain does not exist on the surface of the buffer layer.