Developing a full 3D NEGF simulator with random dopant and interface roughness

摘要

We have developed a full 3D Non Equilibrium Green's Function quantum transport simulator of nanoelectronic devices. In order to illustrate the capabilities of the simulator we have computed the transmission function for silicon nanowires, in the presence of surface roughness and unintentional dopant atoms. Unlike the case of 2D simulations, in which the channel is blocked by the presence of only one impurity, the 3D current flow can turn in 3D avoiding the local impurity potential. This feature counts for a milder effect of the stray impurities and trapped carriers on the current in nanoscaled devices. Another interesting effect is the interference between the reflections of the electron wave function, from multiple impurities in the channel, which produces visible features in the transmission function. The electron density is deformed by the impurity in the channel, which is an effect of the deformation of the transversal electron wave function around the local impurity potential. Similar phenomenon occurs in the case of surface roughness. The above results illustrate the acute need for a three-dimension description of the transport in nano devices in the presence of atomic scale variations in doping and interface configuration.