Method of manufacturing a nitride semiconductor epitaxial substrate
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.
1. A method of manufacturing a nitride semiconductor epitaxial substrate, comprising:
growing a buffer layer on a substrate; and
growing a group III nitride semiconductor layer on the buffer layer,
wherein in the growing the buffer layer, a layer composed of a group III nitride semiconductor containing Al and having an inversion domain on a surface, is formed by a vapor phase epitaxial method, and
wherein in the growing the group III nitride semiconductor layer, a layer formed by embedding a layer grown on the inversion domain by a layer grown on a region other than the inversion domain with C-plane as a surface, is formed by a vapor phase epitaxial method.
2. The method of manufacturing a nitride semiconductor epitaxial substrate according to claim 1 , wherein in the growing the buffer layer, the buffer layer is grown so that a surface density of the inversion domain that exists on the surface is in a range of 1×10 4 cm −2 or more and 1×10 11 cm −2 or less.
3. The method of manufacturing a nitride semiconductor epitaxial substrate according to claim 1 , wherein in the growing the buffer layer, a layer composed of Al x Ga 1-x N(0.5≦x≦1) is grown as the buffer layer.
4. The method of manufacturing a nitride semiconductor epitaxial substrate according to claim 1 , wherein in the growing the buffer layer, the buffer layer is formed by HVPE method, and in the growing the group III nitride semiconductor layer, the group III nitride semiconductor layer is formed by HVPE method.