Quantum simulation of device characteristics of silicon nanowire FETs

A quantum simulation of silicon nanowire field-effect transistors has been performed in the frame work of the effective mass theory, where the three-dimensional Poisson equation was solved self-consistently with the mode-space nonequilibrium Green's function equations in the ballistic transport regime. The dependence of the device performance on the gate length and width for three types of gate configuration has been studied, focusing on the contribution of the tunneling current to the total current. The effects of gate underlap and the corner rounding of silicon body on the device performance have been also investigated quantitatively, leading to the conclusions that the gate underlap is an important factor in improving the subthreshold characteristics of the device, but the corner rounding of silicon body is not a significant factor, especially for devices with silicon body width of a few nanometers.