Three-dimensional simulation study of the improved on/off current ratio in silicon nanowire field-effect transistors

In this paper, we report an approach based on three-dimensional numerical simulations for the investigation of the dependence of the on/off current ratio in silicon nanowire (SiNW) field-effect transistors (FETs) on the channel width. In order to investigate the transport behavior in devices with different channel geometries, we have performed detailed two-dimensional and three-dimensional simulations of SiNWFETs and control FETs with a fixed channel length L and thickness t but varying the channel width W from 5 nm and 5 μm. By evaluating the charge distributions and the current flowlines of both the two- and three-dimensional structures, we have shown that the increase in the 'on state' conduction current in the SiNW channel is a dominant factor, which consequently results in more than a two order of magnitude improvement in the on/off current ratio.