Patent ID: 8716106

Claim:
A method for producing a bonded substrate, comprising at least the steps of: providing a donor wafer formed of one of a silicon substrate and a silicon substrate having a silicon oxide film directly formed on the silicon substrate and a handle wafer having a thermal expansion coefficient lower than the donor wafer, implanting ions of any one or both of hydrogen and a noble gas into the donor wafer to form an ion-implanted layer, performing a surface activation treatment on at least one of bonding surfaces of the donor wafer and the handle wafer, bonding the donor wafer to the handle wafer, thinning the donor wafer to form a silicon film containing only silicon by splitting the donor wafer through application of a mechanical impact to the ion-implanted layer of the donor wafer, performing a surface treatment on a split surface of the silicon film, epitaxially growing at an epitaxial growth temperature of 500° C. to 900° C. a Si 1-x Ge x (wherein x is a number satisfying 0<x≦1) film on the split surface to form a strained Si 1-x Ge x (0<x≦1) film directly on the silicon film of the bonded wafers, and wherein the bonded wafers are subjected to a heat treatment in a temperature range of 100° C. to 350° C. after said step of bonding the donor wafer to the handle wafer, but before said step of thinning the donor wafer.