  A graphene field-effect-transistor (GFET) model calibrated with extracted
device parameters and a commercial 65 nm silicon MOSFET model are compared with
respect to their radio frequency behavior. GFETs slightly lag behind CMOS in
terms of speed despite their higher mobility. This is counterintuitive, but can
be explained by the effect of a strongly nonlinear voltage-dependent gate
capacitance. GFETs achieve their maximum performance only for narrow ranges of
VDS and IDS, which must be carefully considered for circuit design. For our
parameter set, GFETs require at least {\mu} = 3000 cm2 V-1 s-1 to achieve the
same performance as 65 nm silicon MOSFETs.
