A computational study of gate and channel engineering for GNRFETs performance enhancement

Abstract

In this article, the effects of single-material-gate (SMG), halo doping (HALO), triple-material-gate (TMG) and triple-material halo doping (TMG-H) structures on electrical characteristics have been investigated for double gate graphene nanoribbon field-effect transistors (GNRFETs) using a full quantum transport simulation. The simulations are based on non-equilibrium Green’s functions (NEGF) solved self-consistently using 3D-Poisson’s equations. The results reveal that a larger difference between the work functions of gate metals of TMG structure will result in increasing the on–off current ratio in GNRFETs. HALO structure reduces the leakage current and alleviates the short channel effects (SCEs) like drain-induced barrier-lowering. Because of the perceivable steps in surface potential profile, which leads to additional lateral electric field peak along the channel, TMG and TMG-H structures have a larger average lateral electric field along the channel, which significantly promotes the transport efficiency and thus improves the subthreshold characteristics of devices.