Numerical study on the performance metrics of lightly doped drain and source graphene nanoribbon field effect transistors with double-material-gate

In this paper, we perform a theoretical study on the performance metrics of the lightly doped drain and source (LDD) of double-material-gate graphene nanoribbon field effect transistors (GNRFETs). A quantum model based on the non-equilibrium Green's function (NEGF) coupled with a three dimensional Poisson equation under the ballistic limits in the mode space is applied. To highlight the superior performances of LDD structure, comparisons have been made between single-material-gate GNRFETs with conventional doping (C-GNRFETs), single-material-gate GNRFETs with LDD (LDD-GNRFTEs), double-material-gate GNRFETs with conventional doping (DM-GNRFETs) and double-material-gate GNRFETs with LDD (LDD-DM-GNRFETs). The results demonstrates that LDD-DM structure has lower leakage current, better sub-threshold swing performance, larger Ion/Ioff ratio, lower delay time and higher cutoff frequency, which indicates LDD-DM-GNRFETs a promising material for high-speed and lower power applications.