Using the hydrodynamic model of semiconductor devices, the authors simulate an abrupt p-n junction under strong reverse bias, accounting for impact ionization by means of electron and hole generation rates dependent on the carrier temperature. They demonstrate the influence of impact ionization as a cooling mechanism on the mean energy and velocity of the carriers, and show that the ionization coefficients alpha /sub n/ and alpha /sub p/ are spatially retarded with respect to the normally used electric-field dependent ones; this results in larger multiplication factors M/sub n/ and M/sub p/. The reason for this effect is traced back to the increased impact-ionization probability of secondary generated carriers having the chance to travel through a larger portion of the high-field region. This is shown qualitatively by discussing the impact ionization integrals, and is estimated quantitatively through the simulation.>

Monte Carlo simulations of high-energy electrons and holes in Si n-MOSFETs are presented. Key features of this work include the use of a suitable silicon model for carrier transport at high electric fields, an original impact ionization model, and sophisticated numerical techniques to speed up the calculation. The case of submicrometer Si n-MOSFETs is considered as a relevant application.>