Patent ID: 7560350

Claim:
A method for forming a strained semiconductor device, comprising: providing a substrate comprising a first semiconductor material and having a first conductivity type; forming a semiconductor layer of a second conductivity type contacting with the substrate, wherein the semiconductor layer comprises the first semiconductor material and a second semiconductor material and has a dopant of the second conductivity type, and the semiconductor layer is formed with a selective epitaxy growth (SEG) process with in-situ doping of the dopant; and after forming the semiconductor layer with in-situ doping of the dopant, conducting an in-situ annealing to diffuse the dopant, wherein the first semiconductor material is silicon, the second semiconductor material is germanium, the dopant is boron, the SEG process is conducted at about 650-800° C., and the in-situ annealing is conducted ar about 850-950° C.