AN IMPROVED IONIZED IMPURITY SCATTERING MODEL FOR MONTE-CARLO CALCULATIONS

The well known Brooks-Herring (BH) formula for charged-impurity (CI) s cattering overestimates the mobility of electrons in highly doped semi conductors. The BH approach relies on a static, single-site descriptio n of the carrier-impurity interactions neglecting many-particle effect s. We propose a physically based charged-impurity scattering model inc luding Fermi-Dirac statistics, dispersive screening, and two-ion scatt ering. An approximation for the dielectric function is made to avoid n umerical integrations. The resulting scattering rate formulas are anal ytical. Monte Carlo calculations were performed for majority electrons in bulk silicon at 300 K with impurity concentrations from 10(15) cm( -3) to 10(21) cm(-3).