3D real-space quantum transport simulation of nanowire MOS transistors: Influence of the ionized doping impurity

We report a numerical study of both donor- and acceptor doping impurity effects in the quantum transport of silicon nanowire metal-oxide-semiconcluctor (MOS) transistors. The code is based on a full three-dimensional (3D) real-space non-equilibrium green function (NEGF) formalism self-consistently coupled with the 3D Poisson equation. The general results show that the influence of an impurity strongly depends on its type. Indeed, an acceptor or a donor will create a repulsive or attractive potential, giving rise to tunneling effect or resonances, respectively. Our calculations analyze the impact on electron density, transmission coefficient and drain current (I(D)) which undergoes variations up to 50%. This pinpoints the importance of intrinsic fluctuations due to doping in ultimate nano-transistors whose magnitude cannot be neglected in the next generations of integrated circuits. (C) 2008 Elsevier Ltd. All rights reserved.