Patent ID: 7150788

Claim:
A method of preparing an in-plane lattice constant adjusted substrate, characterized in that it comprises the steps of: forming at a first preestablished temperature on a single crystal substrate whose surface is flat on an atomic level, a first epitaxial thin film made of a first material that is different from a material of which the substrate is made; and heat-treating at a second preestablished temperature the substrate having the first epitaxial thin film formed thereon, wherein said first preestablished temperature is a temperature that causes said first epitaxial thin film to epitaxially grow on said substrate; and said second preestablished temperature is a temperature that is higher than said first preestablished temperature but lower than the lower of melting points of said substrate and said first epitaxial thin film, whereby the heat treatment at the second preestablished temperature gives rises to a modification of said substrate such that dislocations are introduced into an interface between the substrate and the first epitaxial thin film whereby the in-plane lattice constant of the first epitaxial thin film is altered to have a value that is close to a bulk lattice constant of said first material, and such that the top surface of said first epitaxial thin film is flattened to an atomic level.