Boltzmann equation analysis of electron swarm behaviour in monosilane

Abstract

The electron swarm behaviour in monosilane is studied for E/p0 from 0.2 to 300 V cm-1 Torr-1 by a Boltzmann equation method. A set of electron collision cross sections is determined by fitting the calculated values of the drift velocity, characteristic energy and effective ionisation coefficient to experimental values. The swarm parameters are calculated for the pulsed Townsend, steady-state Townsend and time-of-flight experiments. Moreover, the accuracy of the two-term approximation is checked by a Monte Carlo simulation. The results show that the calculated values of the effective ionisation coefficient, electron drift velocity and characteristic energy agree well with experimental ones and this suggests that the set of electron collision cross sections determined in the present analysis is an appropriate one, though no unique. It is also found that the electron energy distribution obtained in the present work is represented by a simple Druyvesteyn formula. The excitation frequencies for vibration and dissociation are also calculated and discussed.