GaN substrate and method of fabricating the same, nitride semiconductor device and method of fabricating the same

摘要

A GaN substrate comprises a GaN single crystal substrate, an AlxGa1-xN intermediate layer (0<x<=1) epitaxially grown on the substrate, and an GaN epitaxial layer grown on the intermediate layer. The intermediate layer is made of AlGaN and this AlGaN grows over the entire surface of the substrate with contaminants thereon and high dislocation regions therein. Thus, the intermediate layer is normally grown on the substrate, and a growth surface of the intermediate layer can be made flat. Since the growth surface is flat, a growth surface of the GaN epitaxial layer epitaxially grown on the intermediate layer is also flat.