Effects of microscopic fluctuations in dopant distributions on MOSFET threshold voltage

The effects of fluctuations in dopant distribution on the MOSFET threshold voltage and their dependence on the scaling were investigated using device simulation. The simulation indicates that the microscopic fluctuations in dopant distribution not only induce threshold-voltage value. It was found that the threshold-voltage value deviation is mostly affected by fluctuating dopant distribution at the substrate surface, rather than throughout the depletion layer. Discussion incorporating microscopic fluctuations in surface electric potential, due to fluctuating dopant distribution, explained not only deviations but also the mean value lowering of the threshold voltage in the simulation. >