Patent ID: 7902046

Claim:
A method for growth in the SiGe material system, the method comprising: a) providing a substrate having a top surface; b) growing a buffer structure on the substrate, wherein the growing a buffer structure comprises: i) first growing a first buffer layer comprising Si 1-x Ge x on the top surface of the substrate at a first growth temperature to provide a first intermediate structure; ii) first annealing the first intermediate structure at a first annealing temperature, wherein the first annealing temperature is substantially greater than the first growth temperature; c) growing a SiGe device structure on said buffer structure, wherein a top surface of the buffer structure is substantially lattice matched to the SiGe device structure; wherein said top surface of said substrate has a substrate lattice constant, wherein said first buffer layer has a buffer lattice constant, and wherein the buffer lattice constant and the substrate lattice constant differ by more than 1.5%; wherein said buffer structure has a substantially uniform Ge concentration; wherein said SiGe device structure includes a quantum well having a SiGe well layer sandwiched between SiGe barrier layers, wherein the well layer comprises Si 1-x Ge z , wherein z is greater than about 0.7, whereby the well layer has an indirect band gap and has a conduction band minimum at a center of its Brillouin zone.