Reduction of threading dislocation density in InP-on-Si heteroepitaxy with strained short-period superlattices

Abstract

We applied multistrained short-period superlattices (SSPSs) and GaP buffer layers to the InP-on-Si heteroepitaxy, in order to suppress the generation of threading dislocations. As a result, it was found that the density of threading dislocations in an InP/SSPSs/GaAs/SSPSs/GaP/Si structure including (InAs)m(GaAs)n SSPSs and (GaAs)i(GaP)j SSPSs was remarkably reduced, compared with that in the InP/GaP/Si structure. Misfit dislocations lying along the 〈011〉 directions were observed at heterointerfaces in the InP/SSPSs/GaAs/SSPSs/GaP/Si structure. Therefore, the lattice mismatch strain was stepwise accommodated by the generation of misfit dislocations at the heterointerfaces. From these results, it was clarified that multi-SSPSs are effective for reducing the density of threading dislocations in heteroepitaxy with a large lattice mismatch.