Patent ID: 7723214

Claim:
A process for producing a multilayer structure, comprising: depositing a first SiGe layer directly onto a silicon surface of a substrate, the first SiGe layer having a composition of Si 1-x Ge X and having a lattice constant which differs from the lattice constant of the silicon of the silicon surface; depositing a second SiGe interfacial layer having a thickness of from 2 to 30 nm directly onto the first SiGe layer, the SiGe interfacial layer having a composition of Si 1-y Ge y , the SiGe interfacial layer deposited at a rate of at most 50 nm/min from a gaseous mixture comprising hydrogen, hydrogen halide, silicon compound, and germanium compound, and depositing at least one further layer onto the interfacial layer; wherein the SiGe interfacial layer reduces surface density of threading dislocations originating in the first SiGe layer by termination of threading dislocations at the boundary where the SiGe interfacial layer abuts the first SiGe layer.