Simulation study of channel mobility and device performance dependence on gate stack in graphene field-effect transistors

Abstract

The channel mobility and device performance of graphene field-effect transistors (GFETs) were investigated using a theoretical model. Surface polarized phonon scattering and charged impurity Coulomb scattering are two dominant scattering mechanisms in carrier mobility calculation. Mobilities are used to calculate the drain current and transconductance of GFETs. Adding a polymer buffer layer (PBL) with low permittivity between graphene and gate dielectric can effectively improve GFETs performance at the expense of decreasing gate controllability. PBL thickness was optimized to achieve best device transconductance. Experimental results and the model calculations of both channel mobility and device transconductance are in agreement.