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 and a buffer layer formed of a plurality of lamination units being continuously laminated. The lamination unit includes: a composition modulation layer formed of a first and a second unit layer having different compositions being alternately and repeatedly laminated such that a compressive strain exists therein; a termination layer formed on an uppermost portion of the composition modulation layer, the termination layer acting to maintain the compressive strain existing in the composition modulation layer; and a strain reinforcing layer formed on the termination layer, the strain reinforcing layer acting to enhance the compressive strain existing in the composition modulation layer.

主权项

1. An epitaxial substrate in which a group of group-III nitride layers are formed on a base substrate made of (111)-oriented single crystal silicon such that a (0001) crystal plane of said group of group-III nitride layers is in parallel with the (111) plane of said base substrate, said epitaxial substrate comprising a buffer layer formed of a plurality of lamination units being continuously laminated; and
a crystal layer formed on said buffer layer, each of said lamination units including:
a composition modulation layer formed of a first unit layer and a second unit layer having different compositions being alternately and repeatedly laminated such that a compressive strain exists therein;a termination layer formed on an uppermost portion of said composition modulation layer, said termination layer acting to maintain said compressive strain existing in said composition modulation layer; anda strain reinforcing layer formed on said termination layer, said strain reinforcing layer acting to enhance said compressive strain existing in said composition modulation layer.