Influence of band-structure on electron ballistic transport in silicon nanowire MOSFET´s: an atomistic study

This work investigates the conduction band structure of silicon nanowires, its dependence with the wire width and its consequences on the electrical performances of Si nanowire-based MOSFETs working in the ballistic regime. The energy dispersions relations for Si nanowires have been calculated using a sp³ tight-binding model and the ballistic response of n-channel devices with a 3D Poisson-Schrodinger solver considering a mode space approach and open boundary conditions (NEGF formalism). Results are compared with data obtained considering the parabolic bulk effective-mass approximation, highlighting in this last case the overestimation of the I_on current, up to 60% for the smallest (1.36nm × 1.36nm Si wire) devices.