Advancing quasi-freestanding epitaxial graphene electronics through integration of wafer scale hexagonal boron nitride dielectrics

摘要

A key limitation to graphene based electronics is graphene’s interaction with dielectric interfaces. SiOsub2/sub andvarious high-k gate dielectrics can introduce scattering from charged surface states, impurities, and surface opticalphonons; degrading the transport properties of graphene. Hexagonal boron nitride (h-BN) exhibits an atomically smoothsurface that is expected to be free of dangling bonds, leading to an interface that is relatively free of surface charge trapsand adsorbed impurities. Additionally, the decreased surface optical phonon interaction from h-BN is expected to furtherreduce scattering. While h-BN gated graphene FETs have been demonstrated on a small scale utilizing CVD grown orexfoliated graphene, integrating quasi-freestanding epitaxial graphene (QFEG) with h-BN gate dielectrics on a waferscale has not been explored. We present results from the first large scale CVD growth of h-BN and its subsequenttransfer to a 75mm QFEG wafer. The effects of growth conditions on the thickness and quality of the h-BN film and itspotential and limitations as a gate dielectric to QFEG are discussed. The introduction of charged impurities during thetransfer process resulted in an average degradation in mobility of only 9%. Despite the slight degradation, we show thath-BN is highly beneficial compared to high-k dielectrics when the charged impurity concentration of QFEG is below5x10sup12/supcmsup-2/sup. Here we show improvements in mobility of &3x and intrinsic cutoff frequency of &2x compared to HfOsub2/sub.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.