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 Trigate 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 (Vth) 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 Vth variation. The Vth dispersion of Tri-gate may therefore be smaller than that of FinFET because of its better immunity to dopant number fluctuation.
- 3-D Poisson's equation
- Multigate MOS-FETs