Comparison of RF performance between 20 nm-gate bulk and SOI FinFET

Due to their 3D architecture, FinFETs exhibit a strong dependence of RF figures-of-merit on device geometry due to large extrinsic resistances and capacitances. We analyze the RF performance of 20-nm gate length FinFETs implemented on either bulk or SOI substrate by using 3D numerical device simulation. SOI and bulk FinFET are compared in terms of cut-off and maximum oscillation frequency, gate capacitance and trans-conductance. We have proposed and investigated the influence of different doping methods that aim at improving the RF figures-of-merit of 20 nm bulk FinFETs while maintaining acceptable DC performance.