Quantitative SEM-EDS Analysis of Semi-Transparent Samples

Abstract

Recent years have seen increased crossover of microscopy techniques developed for transmission electron microscopes (TEMs) being utilized as well in scanning electron microscopes (SEMs). The order of magnitude lower beam energies available in SEMs correspond with significantly different beam-sample interactions that must be accounted for when examining freestanding films. This is especially important for composition analysis via energy dispersive X-ray spectroscopy (EDS) since lower-energy transmission experiments mean X-ray volumes become comparable to sample dimensions. To better understand this scenario, we report results of an SEM-EDS study of terraced freestanding films comprising binary compounds with well-defined atomic ratios. Guided by Monte Carlo simulations, EDS line scan data were collected at different beam energies across segments of varying thicknesses. The results of quantification analysis using different models are compared for multiple combinations of beam energy, sample thickness, and material density, from which some general guidelines are provided for SEM-EDS analysis of freestanding films.