Imaging with surface sensitive backscattered electrons

Abstract

This article presents simulation and experimental results of an angle-filtered backscattered electron (BSE) technique in the scanning electron microscope (SEM). Simulation results predict that for an incident primary beam energy of 5 keV, BSEs with low emission angles (90°-91°) contain scattering information coming mostly from within 2 nm below the specimen surface. A buried layer track is tested with a 10 keV primary beam inside a normal SEM. The BSE image at low emission angles (between 90° and 91°) provides only surface contamination details while the buried layer is not present. This result indicates that the low emission angle BSEs can be used for surface sensitive imaging. © 2007 American Vacuum Society.