High-frequency analog GNR-FET design criteria

Abstract

Some key aspects of the behavior of graphene nanoribbon (GNR) FETs for high-frequency analog applications are identified and discussed by means of a simulation study based on a full-quantum ballistic transport model. GNRs of width in the order of 10 nm are considered, where the small band-gap and the consequent leakage currents due to band-to-band-tunneling (BTBT) require a careful design. Simulations performed with a realistic model for source/drain metal contacts indicate that a proper choice of the drain doping profile can partially suppress BTBT currents. A 40-nm gate-length 2-nm SiO2 gate-dielectric GNR-FET can achieve a peak small-signal voltage gain of about 30 and a cut-off frequency well above 1 THz.

Simulation of 50-nm Gate Graphene Nanoribbon Transistors

“…Experimental GNR MOSFETs could not be included in Figure 11 since the RF performance of such transistors has not been reported so far. [21,22,47,48] and from the present work. f T data of experimental GFETs and data taken from the compilations in are also shown [5,6].…”

“…This configuration has only a top gate and no interribbon gate and for its investigation 2D device simulations are sufficient. We note that such single-channel devices have been considered in most previous theoretical investigations of GNR MOSFETs [21][22][23][24][25][26][27].…”

“…This configuration has only a top gate and no interribbon gate and for its investigation 2D device simulations are sufficient. We note that such single-channel devices have been considered in most previous theoretical investigations of GNR MOSFETs [21][22][23][24][25][26][27]. Figure 5a shows the simulated transfer characteristics of the 50-nm gate single-channel N = 7 ac GNR MOSFET for a drain-source voltage V DS of 1 V. We define transistor's threshold voltage V Th as the gate-source voltage for which at V DS = 1 V a drain current of 10´7 Aˆw/L flows and the effective gate-source voltage V GS´e f f is related to the applied gate-source voltage V GS by V GS´e f f = V GS´VTh .…”

“…Steady-state quantum simulations based on the NEGF (nonequilibrium Green's function) approach assuming ballistic transport have been performed [21][22][23][24][25] and GNR MOSFET simulations taking edge scattering [26,27] and phonon scattering [25] into account have been conducted. Moreover, the RF performance of GNR MOSFETs has been investigated by numerical simulations [21,22,25] and analytical equations have been developed to calculate the steady-state behavior and the RF properties of GNR MOSFETs [28].…”

“…This has led to overly optimistic performance predictions such as unrealistically high simulated cutoff frequencies [21,22,25,28]. Moreover, most simulations have been performed using in-house tools not accessible by the community.…”