Hole mobility enhancement in extremely-thin-body strained GOI and SGOI pMOSFETs by improved Ge condensation method

We demonstrate high performance extremely-thin-body (ETB) Ge-on-insulator (GOI) and SiGe-on-insulator (SGOI) pMOSFETs with the body thickness ranging from 10 to 2 nm by applying the improved Ge condensation process with slow cooling to initial substrates with thinner SiGe layers. When we employ Si/40-nm-thin Si0.75Ge0.25/SOI structures as starting substrates for Ge condensation, the high compressive strain of ~1.75% is maintained in GOI, leading to the operation of 10-nm-thick GOI pMOSFETs with hole mobility (µh) of 467 cm2/Vs. Furthermore, by thinning the fabricated GOI and SGOI films, we demonstrate the operation of ETB GOI and SGOI pMOSFETs with the body thickness down to 2 nm without losing high compressive strain. Comparing with the reported results, the record-high µh is obtained in GOI pMOSFETs in the GOI thickness ranging from 10 to 2 nm.