Sensitivity of Multigate mosfets to Process Variations–-An Assessment Based on Analytical Solutions of 3-D Poisson\´s Equation

This paper investigates the sensitivity of multigate MOSFETs to process variations using analytical solutions of 3-D Poisson´s equation verified with device simulation. FinFET and Tri- gate with both heavily doped and lightly doped channels have been examined regarding their immunity to process-induced variations and dopant number fluctuation. Our study indicates that lightly doped FinFET has the smallest threshold voltage (V_th) dispersion caused by process variations and dopant number fluctuation. For heavily doped devices, dopant number fluctuation may become the dominant factor in the determination of overall V_th variation. The V_th dispersion of Tri-gate may therefore be smaller than that of FinFET because of its better immunity to dopant number fluctuation.