(Invited) Mobility Enhancement Technology of Extremely-Thin Body Ge-on-Insulator Channel Mosfets

An extremely thin body (ETB) channel is mandatory for scaled nano-sheet structures to realize continuous miniaturization of CMOS devices. Here, mobility booster technologies to maintain high channel mobility are strongly needed, because surface roughness scattering significantly reduces mobility in such ETB channels. From this viewpoint, Ge-On-Insulator (GOI) or SiGe-On-Insulator (SGOI) channels are promising because of the low electron and hole effective mass along channel directions. It is theoretically shown that (111) GOI n-MOSFETs can hold high electron mobility even in the body thickness down to 2 nm. Thus, (111) GOI structures and n-MOSFETs are fabricated, and the electrical characteristics are studied. For p-MOSFETs, on the other hand, (110) surface orientation and application of compressive strain are still effective in boosting hole mobility in ETB channels. Here, (110) asymmetric compressive strain SGOI p-MOSFETs are experimentally demonstrated, and the body thickness dependencies of the effective mobility are examined.