Three-dimensional statistical modeling of the effects of the random distribution of dopants in deep sub-micron nMOSFETs

The purpose of this work is to evaluate the effects of intrinsic fluctuations of the discrete distribution of dopants on the threshold voltage and on the off-state current of n-MOSFETs. We use a model taking into account the Fermi-Dirac statistics of electrons and holes, a polysilicon gate, and the effect of doping fluctuations in the polysilicon gate, source and drain. In addition, we also consider the dispersion of the off-state current, which leads to an overall increase of the standby power dissipation. We will present results obtained with definitions of the threshold voltage based on the subthreshold current and on the linear extrapolation of the input characteristics, and will compare them with analytical models and numerical 1D simulations.