Analysis of threshold voltage variations in fin field effect transistors

To conduct analyses of variability of threshold voltage (Vth) in FinFETs whose structures are based on the ITRS, sensitivity coefficients of variations of Vth caused by the fluctuation of principal device parameters were derived by device simulation. The sensitivity coefficient correlated with each device parameter was separated into two factors: one due to an intrinsic mechanism (1D factor) and another due to short-channel effects (2D factor). The 1D and 2D factors were found to cancel each other out in some cases, thereby reducing the sensitivity coefficient. Based on these results, FinFETs with various structures were examined and controlling short-channel effects was demonstrated to be an effective way to reduce the variation in the threshold voltage