Effect of Random, Discrete Source Dopant Distributions on Nanowire Tunnel FETs

The finite number, random placement, and discrete nature of the dopants in the source of an InAs nanowire tunnel field-effect transistor affect the drive current and the inverse subthreshold slope. The impact of source scattering is negligible, since the current is limited by the interband tunneling. The most significant effect of the discrete dopants is to create variations of the electric fields in the tunnel barrier, which cause variations in the current. The relative variation in the ON current decreases as the average doping density and/or nanowire diameter increases. Results from full self-consistent nonequilibrium Green´s function calculations and semiclassical calculations are compared.