A small-signal, RF simulation study of multiple-gate and silicon-on-insulator MOSFET devices

Because of their superior scaling characteristics and reduced short channel effects, multi-gate MOSFETs are being considered for replacing conventional planar silicon MOSFETs in digital applications. At the same time, improvements in the high frequency capabilities of conventional MOSFETs have made them increasingly attractive for RF applications. The paper examines the performance capabilities of multi-gate MOSFETs in the RF regime using a simulation study of their small-signal behavior. Three dimensional numerical simulations have been performed to investigate the high frequency performance of two of the most promising multigate devices, i.e. the finFET and the trigate transistor. The trigate transistor has been found to exhibit a higher transconductance, small signal current gain and unilateral power gain as compared to the finFET, as well as a higher cutoff frequency, f_T, and maximum frequency of oscillation, f_MAX. Peak f_T of 42 and 51 GHz and peak f_MAX of 183 and 228 GHz were obtained for the finFET and trigate transistors, respectively, for a gate length of 50 nm.