Patent ID: 7550309

Claim:
A method for producing a semiconductor wafer, comprising at least steps of: (1) epitaxially growing a Si 1-X Ge X layer (0<X<1) on an SOI wafer; (2) forming a Si 1-Y Ge Y layer (0≦Y<X) on the epitaxially grown Si 1-X Ge X layer; (3) and then enriching Ge in the epitaxially grown Si 1-X Ge X layer by an oxidation heat treatment so that the Si 1-X Ge X layer becomes an enriched SiGe layer; and (4) performing a heat treatment for relaxing the lattice in the enriched SiGe layer under an argon or nitrogen atmosphere; wherein, at least, the oxidation heat treatment is (3a) initiated from 950° C. or less under an oxidizing atmosphere, and the oxidation is performed so that the formed Si 1-Y Ge Y layer remains during a temperature rise to 950° C.; and then after the temperature rise to 950° C. (3b) performed by raising the temperature to 1200° C. or more under an argon or nitrogen atmosphere containing oxygen of 5% or less, thereby performing the oxidation until the remaining Si 1-Y Ge Y layer is made to disappear; and then, (3c) performed by performing oxidation under an oxidizing atmosphere to perform the enrichment of Ge.