Model improvements to simulate charging in scanning electron microscope

Abstract

Background: Charging of insulators is a complex phenomenon to simulate since the accuracy of the simulations is very sensitive to the interaction of electrons with matter and electric fields. Aim: In this study, we report model improvements for a previously developed Monte-Carlo simulator to more accurately simulate samples that charge. Approach: The improvements include both modeling of low energy electron scattering by first-principle approaches and charging of insulators by the redistribution of the charge carriers in the material with an electron beam-induced conductivity and a dielectric breakdown model. Results: The first-principle scattering models provide a more realistic charge distribution cloud in the material and a better match between noncharging simulations and experimental results. The improvements on the charging models, which mainly focus on the redistribution of the charge carriers, lead to a smoother distribution of the charges and better experimental agreement of charging simulations. Conclusions: Combined with a more accurate tracing of low energy electrons in the electric field, we managed to reproduce the dynamically changing charging contrast due to an induced positive surface potential.