Monte Carlo calculation of electron backscattering coefficients for Fe and Ni solids

Abstract

We have calculated the electron backscattering coefficients η(Ep) for elemental solids, Fe and Ni, for primary electron energies of 0.1–100 keV, by utilizing a state-of-the-art Monte Carlo simulation model. A relativistic dielectric functional approach was applied to calculate the electron inelastic cross section, incorporating various data sets of the optical energy loss function (ELF). The calculation results reveal that the backscattering coefficient is profoundly affected by the ELF, conforming to the f-sum and ps-sum rules. To evaluate uncertainties in relation to experimental data, we examined the systematic errors related to contaminated surfaces. Simulations of Fe and Ni surfaces contaminated with carbonaceous atomic layers successfully accounted for the trend of the observed experimental data. Our findings indicate that precise backscattering coefficient value should either be measured from thoroughly cleaned surfaces or calculated from the Monte Carlo simulation that utilize reliable optical constant data. These simulation data have worth in multiple scientific fields particularly for the application of scanning electron microscopy. Given recent advancements in the accurate measurement of optical constants through reflection electron energy loss spectroscopy, there is considerable promise for developing a robust theoretical database of electron backscattering coefficients for the clean surfaces of elemental solids.