Electron transport studies in SiO2 films excited by a pulsed electron beam

Abstract

Charge transport in steam-grown thin films of silicon dioxide (SiO2) is studied using a short-duration pulse of energetic electrons for generating hole-electron pairs in the oxide. Within the time resolution of the measuring circuitry ( approximately 1 ns) electron transport follows the excitation pulse exactly. It is shown that electron-beam-induced currents in SiO2 are limited by geminate or columnar recombination processes and that the incorrect application of the normal photoconduction equation to experimental data leads to invalid thickness-dependent mobility-lifetime products ( mu tau ). The present measurements indicate that for electron mu tau >>1.2*10-13 m2 V-1 and mu >1.2*10-4 m2 V-1 s-1.