Experimental evidence of increased deformation potential at MOS interface and its impact on characteristics of ETSOI FETs

Deformation potential (D_ac), which determines the strength of electron-phonon scattering, is one of the most important physical parameters of Si. A longstanding unresolved question in D_ac is that D_ac for MOSFETs is considered to be much greater than D_ac for bulk Si. In this work, we have demonstrated for the first time that D_ac increases sharply at MOS interfaces within several-nm range. Because of the enhanced D_ac at MOS interface, D_ac for nanoscale SOI channel is expected to be increased owing to the high surface-to-volume ratio, which is verified by electron mobility calculations in extremely-thin SOI (ETSOI) MOSFETs and experimental stress-induced mobility enhancement in nanoscale SOI.