Simulation of scanning electron microscope images taking into account local and global electromagnetic fields

Abstract

The authors report the development of a simulation tool with unique capabilities to comprehensively model a scanning electron microscope (SEM) signal. This includes electron scattering, charging, and detector settings, as well as modeling of the local and global electromagnetic fields and electron trajectories in these fields. Experimental and simulated results were compared for SEM imaging of carbon nanofibers embedded into bulk material in the presence of significant charging as well as for samples with applied potential on metal electrodes. The effect of the potentials applied to electrodes on the secondary emission was studied; the resulting SEM images were simulated. The image contrast depends strongly on the sign and the value of the potential. SEM imaging of nanofibers embedded into silicon dioxide resulted in the considerable change in the apparent dimensions of the fibers as well as tone reversal when the beam voltage was varied. The results of the simulations are in agreement with experimental results.