Time-dependent start-up and decay of secondary electron emission in dielectrics

Electron beam induced selfconsistent charge transport and secondary electron emission in insulators are described by means of an electron-hole flight-drift model implemented by an iterative computer simulation. Ballistic secondary electrons and holes, their attenuation and drift, as well as their recombination, trapping, and field-dependent and temperature-dependent detrapping are included. As a main result the time dependent secondary electron emission rate σ(t) and the spatial distributions of currents j(x,t), charges ρ(x,t), field F(x,t), and potential V(x,t) are obtained. Whereas the switching-on of the secondary electron emission proceeds over milliseconds due to selfconsistent charging, the switching-off process occurs much faster, even over femtoseconds.