EPITAXIAL SUBSTRATE AND METHOD FOR MANUFACTURING EPITAXIAL SUBSTRATE

摘要

Provided is a crack-free epitaxial substrate having a small amount of warping, in which a silicon substrate is used as a base substrate. The epitaxial substrate includes a (111) single crystal Si substrate, a buffer layer, and a crystal layer. The buffer layer is formed of a first lamination unit and a second lamination unit being alternately laminated. The first lamination unit includes a composition modulation layer and a first intermediate layer. The composition modulation layer is formed of a first unit layer and a second unit layer having different compositions being alternately and repeatedly laminated so that a compressive strain exists therein. The first intermediate layer enhances the compressive strain existing in the composition modulation layer. The second lamination unit is a second intermediate layer that is substantially strain-free.