Numerical simulation of crystallographic direction-dependent impact ionization process on GaAs

摘要

The impact ionization rates in GaAs are derived from a first principle's calculation which includes realistic band structure, and well fitted to modified Keldysh formula with power exponents of 4.44 and 8.08, at 300 and 77 K, respectively. The impact ionization coefficients calculated from a full-band Monte Carlo simulation agree well with available experimental data. The impact ionization process at 77 K is more anisotropic than one of 300 K since influence of electric field is stronger due to low phonon scattering rate and impact ionization is frequently occurred at low energy, where anisotropic property is strong.