High mobility strained ge pMOSFETs with high-κ/metal gate

Compressively strained Ge long channel ring-type pMOSFETs with high-kappa Si/SiO2/HfO2/TiN gate stacks are fabricated on Si0.2Ge0.8 virtual substrates. Effective oxide thickness is approximately 1.4 nm with low gate leakage current. A peak hole mobility of 640 cm(2)/V center dot s and up to a four times enhancement over the Si/SiO2 universal curve are observed. Parasitic conduction within the Si-cap layers degrades the mobility at large vertical fields, although up to a 2.5 times enhancement over universal remains at a field of 0.9 MV/cm.