Heteroepitaxial semiconductor device including silicon substrate, gaas

Abstract

A semiconductor device includes an Si substrate, a stress absorbing layer of GaAs and disposed on the Si substrate, a buffer layer having a composition of Al.sub.x Ga.sub.1-x-y In.sub.y N (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1) and disposed on the stress absorbing layer, and a compound semiconductor layer having a composition of Al.sub.x Ga.sub.1-x-y In.sub.y N (0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1) and disposed on the buffer layer. Therefore, the buffer layer protects the GaAs stress absorbing layer from high temperatures during the formation of the compound semiconductor layer, whereby the stress absorbing layer is prevented from decomposition. As a result, a stress due to lattice mismatch or thermal stress between the Si substrate and the compound semiconductor layer is absorbed in the GaAs stress absorbing layer having a lowest bulk modulus, whereby a compound semiconductor layer with reduced dislocations may be grown on the buffer layer and bending of the Si substrate prevented.