Strained ultrahigh performance fully depleted nMOSFETs with f_t of 330 GHz and sub-30-nm gate lengths

Abstract

Ultrahigh performance fully depleted nMOSFETs have been fabricated on ultra-thin silicon-on-insulator (UTSOI) with a body thickness of 18 nm and channel lengths down to 20 nm. Uniaxial tensile stress induced in the channel using stressed contact liners and stress memorization was found to significantly improve ac performance, resulting in cutoff frequencies ft value reported on fully depleted UTSOI MOSFETs and is among the highest fT values for any Si-based field-effect transistor. Stress memorization and stressed contact liners were found to have little impact on gate to source capacitance indicating that the enhancement in fT results primarily from stress-induced enhancements in transconductance. © 2006 IEEE.