MONTE-CARLO SIMULATION OF IMPACT IONIZATION AND CURRENT MULTIPLICATION IN SHORT GAAS P(+)IN(+) DIODES

We have modelled carrier transport and impact ionization in bulk GaAs and GaAs p(+)in(+) diodes using two Monte Carlo models, one using anal ytical band structure, the other employing more realistic pseudopotent ial band structure. Despite the relative lack of sophistication of the analytical model and the poor representation of band structure at hig her energies, the analytical model reproduced accurate drift velocitie s, mean energies and impact ionization rates in good agreement with ex periment and the more sophisticated model. Both models accurately simu lated the p(+)in(+) diodes, agreeing well with experimental results an d the two models also agreed with each other with respect to the micro scopic aspects of the carrier transport in these devices.