Patent ID: 8440547

Claim:
A method of forming a structure having an engineered SiGe channel comprising: providing a semiconductor substrate having at least one active area with an exposed upper semiconductor surface; forming a SiGe layer on the exposed upper semiconductor surface of the active area; subjecting said SiGe layer to heating in an oxidizing ambient, wherein said heating converts only the SiGe layer into an oxidized SiGe layer and forms a surface oxide layer on the oxidized SiGe layer, wherein said oxidized SiGe layer has a lower surface located directly on said exposed upper semiconductor surface of the active region of the semiconductor substrate; removing the surface oxide layer exposing an upper surface of the oxidized SiGe layer; and forming a Si cap on the exposed upper surface of the oxidized SiGe layer, wherein said Si cap and said oxidized SiGe layer form a SiGe film on the exposed upper surface of the active area, said SiGe film including a lower region that has a first Ge concentration and comprised of said oxidized SiGe layer, and an upper region that has a second Ge concentration and comprised of said Si cap, wherein the first Ge concentration is greater than the second Ge concentration.