Patent ID: 7202139

Claim:
A method of forming a strained semiconductor layer, comprising the steps of: providing a first wafer with a surface comprising of a first semiconductor layer of a first natural lattice constant, wherein said first semiconductor layer is an alloy semiconductor layer comprising silicon and germanium, with a Ge mole fraction between about 5 to 80%; forming a second semiconductor layer with a second natural lattice constant on the first semiconductor layer, said first and second natural lattice constants being different so as to introduce a strain gradient at the interface of said second semiconductor layer and said first semiconductor layer; providing a second wafer with a surface with or without an insulator layer; bonding said second semiconductor layer on said surface of said second wafer, resulting in a third wafer comprised of said second wafer, said second semiconductor layer, and said first wafer; and performing a water jet cleaving procedure at said strain gradient so that said second semiconductor layer is separated from said first semiconductor layer and said first wafer due to cleaving facilitated by said strain gradient.