An efficient numerical approach to studying impact ionization in sub-micrometer devices

Abstract

A positive feedback model is introduced to facilitate numerical calculations of the impact-ionization current gain in sub-micrometer devices. Demonstrations of this model's applicability are done through Monte Carlo simulations to fit the experimental data of short p-i-n diodes. It is shown from the simulations' results that the phonon-collision broadening effect and the intra-collisional field effect play an important role in the II process in deep sub-micrometer devices. It is also shown, for the first time, that the impact-ionization rates at very low energies can be extracted from the measured current gain in short p-i-n diodes.