A study of quantum transport in end-of-roadmap DG-MOSFETs using a fully self-consistent Wigner Monte Carlo approach

We present results of ultrascaled double-gate MOSFET operation and performance obtained from a new self-consistent particle-based quantum Monte Carlo (MC) approach. The simulation of quantum transport along the source-drain direction is based on the Wigner transport equation and the mode-space approximation of multi subband description. An improved method for correctly reproducing the Wigner function in the phase space by means of pseudo-particles is proposed. Our approach includes scattering effects for a two-dimensional (2-D) electron gas via standard MC algorithm. Detailed comparisons with both ballistic nonequilibrium Green's function and semiclassical multi subband Monte Carlo approaches show the ability of this Wigner transport model to incorporate correctly quantum effect into particle ensemble Monte Carlo simulation together with accurate description of scattering. This study of 6-nm-long MOSFET emphasizes the prevalent contribution of source-drain tunneling in subthreshold regime and the significant effect of quantum reflections in on-state. The influence of scattering in both the source access region and the gated part of the channel appears to be of prime importance for the correct evaluation of the on-state current, even for such small device in which the fraction of ballistic electrons is high.