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

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 (f_S) and intrinsic gain (A_V) have been calculated as ~12 THz and 20, respectively (at low bias of gate-to-source voltage, V_GS = 0.1 V and drain-to-source voltage, V_DS = 0.1 V), for single gate configuration. However, for double gate, A_V becomes ~2.5 times higher but f_S 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 A_V, f_S, dynamic power (P_DYN) 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 I_ON and f_S compare very favorably with both current International Technology Roadmap for Semiconductors (ITRS) Road Map specifications and available experimental results for GNRFET.