Effect of gate electrode work function in conventional and junctionless FinFETs

This paper investigates the effect of gate electrode work function in 30 nm gate length conventional and junctionless FinFETs using technology computer-aided design (TCAD) simulations. DC parameters, threshold voltage (vt), drive current (Ion) and output resistance (Ro), and RF parameters, unity gain cutoff frequency (ft), non-quasi static (NQS) delay and input impedance (Z11) are investigated. Junctionless devices being bulk conductive behaves differently with respect to work function variation compared to surface conducting conventional devices. The rate of change in Vt and Ion with respect to work function, in junctionless devices, is slower compared to conventional devices. Owing to better drain induced barrier lowering (DIBL) performance, junctionless devices have higher output resistance. In conventional devices, ft is not sensitive for most of the work function range due to the screening effect of the inversion layer whereas junctionless device shows strong dependency on the work function.