Patent ID: 7442657

Claim:
A method of producing a stress relaxed monocrystalline layer structure on a nonlattice matched substrate, the method comprising the steps of: applying to the substrate epitaxially a monocrystalline layer structure comprising at least one layer, the monocrystalline layer structure forming with the substrate an interface that has a greater lattice parameter mismatch on the substrate than within the monocrystalline layer structure, selecting an overall layer thickness of the monocrystalline layer structure so that a dislocation density following growth is less than 10 3 cm −2 , irradiating the monocrystalline layer by directing a beam of ions through the monocrystalline layer structure to generate predominantly point effects in the monocrystalline layer structure and an extended defect region in the substrate proximal to the monocrystalline layer structure, selecting an energy of the ions such that a mean range of the ions is greater than the total layer thickness of the monocrystalline layer structure, and thermally treating the monocrystalline layer structure after irradiation by the ion beam in a temperature range of 550° C. to 1000° C. in an inert, reducing or oxidizing atmosphere so that the monocrystalline layer structure above the extended defect region is stress relaxed and has a defect density less than 10 6 cm −2 and a surface roughness of less than 1 nm.