A new model for the impact ionization using the tail electron density
is proposed. A new hydrodynamic model is used to compute the tail carr
ier quantities. The discretization method and numerical procedures are
explained. The model parameters are extracted from the space-dependen
t Monte Carlo simulations. The simulated results for an n+ - n- - n+ d
iode and a DILDD n-MOSFET are shown and give good agreement with Monte
Carlo simulations and measurements, respectively.