US Patent 8008157 CMOS device with raised source and drain regions

A method of forming a semiconductor structure includes forming a PMOS device and an NMOS device. The step of forming the PMOS device includes forming a first gate stack on a semiconductor substrate; forming a first offset spacer on a sidewall of the first gate stack; forming a stressor in the semiconductor substrate using the first offset spacer as a mask; and epitaxially growing a first raised source/drain extension (LDD) region on the stressor. The step of forming the NMOS device includes forming a second gate stack on the semiconductor substrate; forming a second offset spacer on a sidewall of the second gate stack; epitaxially growing a second raised LDD region on the semiconductor substrate using the second offset spacer as a mask; and forming a deep source/drain region adjoining the second raised LDD region.