Energy-weighted dynamical scattering simulations of electron diffraction modalites in the scanning electron microscope

Pascal, Elena and Singh, Saransh and Callahan, Patrick G. and Hourahine, Ben and Trager-Cowan, Carol and De Graef, Marc (2018) Energy-weighted dynamical scattering simulations of electron diffraction modalites in the scanning electron microscope. Ultramicroscopy, 187. pp. 98-106. ISSN 0304-3991

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    Abstract

    Transmission Kikuchi diffraction (TKD) has been gaining momentum as a high resolution alternative to electron back-scattered diffraction (EBSD), adding to the existing electron diffraction modalities in the scanning electron microscope (SEM). The image simulation of any of these measurement techniques requires an energy dependent diffraction model for which, in turn, knowledge of electron energies and diffraction distances distributions is required. We identify the sample-detector geometry and the effect of inelastic events on the diffracting electron beam as the important factors to be considered when predicting these distributions. However, tractable models taking into account inelastic scattering explicitly are lacking. In this study, we expand the Monte Carlo (MC) energy-weighting dynamical simulations models used for EBSD [1] and ECP [2] to the TKD case. We show that the foil thickness in TKD can be used as a means of energy filtering and compare band sharpness in the different modalities. The current model is shown to correctly predict TKD patterns and, through the dictionary indexing approach, to produce higher quality indexed TKD maps than conventional Hough transform approach, especially close to grain boundaries.