Investigations of analog/RF performance for underlap graphene nano-ribbon field effect transistor (GNRFET)

Abstract

Single gate and double gate GNRFETs with 5-20% doping of potassium (K) in source (S), drain (D) and channel region having width (W)=2 and 5 nm have been synthesized. On-to-off current ratio (Ion/Ioff) and sub-threshold swing (S) for single gate GNRFET having W=2nm with 10% of K doping have been found to be ~10 and ~20mV/dec, respectively whereas these value for double gate have been found ~10 and ~17mV/dec. Intrinsic speed (fS) and intrinsic gain (AV) have been calculated as ~12 THz and 20, respectively (at low bias of gate-to-source voltage, VGS = 0.1 V and drain-to-source voltage, VDS = 0.1 V), for single gate configuration. However, for double gate, AV becomes ~2.5 times higher but fS is reduce by ~20%. Furthermore, the device follows a square-law, which would greatly suppress odd-order harmonics and improves dynamic range in designing of low power communication system. Using a new figure-of-merit (FoM) involving AV, fS, dynamic power (PDYN) and off state leakage power (Poff) consumption, it has been found that double gate GNRFET gives significant advantage over carbon nano-tubes (CNTs) FET and single gate GNRFET having similar dimensions. The on current ION and fS compare very favorably with both current International Technology Roadmap for Semiconductors (ITRS) Road Map specifications and available experimental results for GNRFET.