Quantitative Evaluation of Statistical Variability Sources in a 45-nm Technological Node LP N-MOSFET

A quantitative evaluation of the contributions of different sources of statistical variability, including the contribution from the polysilicon gate, is provided for a low-power bulk N-MOSFET corresponding to the 45-nm technology generation. This is based on a joint study including both experimental measurements and ldquoatomisticrdquo simulations on the same fully calibrated device. The position of the Fermi-level pinning in the polysilicon bandgap that takes place along grain boundaries was evaluated, and polysilicon-gate-granularity contribution was compared to the contributions of other variability sources. The simulation results indicate that random discrete dopants are still the dominant intrinsic source of statistical variability, while the role of polysilicon-gate granularity is highly dependent on Fermi-level pinning position and, consequently, on the structure of the polysilicon-gate material and its deposition and annealing conditions.