The study of electron mobility on ultra-scaled silicon nanosheet FET

Abstract

The nanosheet FET (NSFET) is the successor to FinFET, and its mobility significantly affects device performance. In this paper, we investigate the impact of phonon (ph) and surface roughness (SR) scattering on the electron mobility of n-type silicon NSFETs. The effects of channel width, thickness, and doping concentrations on NSFETs' mobility are also analyzed. Non-Equilibrium Green’s Function (NEGF) solver which incorporates scattering mechanisms using the self-energy formulation is employed. The mobility behavior in NSFETs is strongly affected by ph scattering and SR scattering. As for ultrathin nanosheets, severe mobility degradation is dominated by SR scattering. The mobility is slightly affected by the doping concentrations. Simulation results provide guidance to researchers and industry in understanding and predicting the variation of mobility under the trend of continuous scaling.