pMOSFET with 200% mobility enhancement induced by multiple stressors

Recessed Si/sub 0.8/Ge/sub 0.2/ source/drain (S/D) and a compressive contact etch-stop layer have been successfully integrated resulting in nearly 200% improvement in hole mobility. This is the largest reported process-induced hole mobility enhancement to the authors' knowledge. This letter demonstrates that a drive-current improvement from recessed Si/sub 0.8/Ge/sub 0.2/ plus the compressive nitride layer are in fact additive. Furthermore, it shows that the mobility enhancement is a superlinear function of stress, leading to larger than additive gains in the drive current when combining several stress sources.