Thickness measurements with electron energy loss spectroscopy

Abstract

Measurements of thickness using electron energy loss spectroscopy (EELS) are revised. Absolute thickness values can be quickly and accurately determined with the KramersKronig sum method. The EELS data analysis is even much easier with the log-ratio method, however, absolute calibration of this method requires knowledge of the mean free path of inelastic electron scattering k. The latter has been measured here in a wide range of solids and a scaling law k $ q 20.3 versus mass density q has been revealed. EELS measurements critically depend on the excitation and collection angles. This dependence has been studied experimentally and theoretically and an efficient model has been formulated. Microsc. Res. Tech. 71:626-631, 2008. V

Accurate measurement of absolute experimental inelastic mean free paths and EELS differential cross-sections

“…ρ is to be used to find λ B using the Iakoubovskii parameterisation [29]. The resulting values are not sensitive to the exact stoichiometries.…”

“…Again, these have not been explored in detail. The use of the Iakoubovskii parameterisation [29] may also be a source of error but the self-consistency of the results suggests that this could only be a small effect.…”

“…A measurement of λ is carried out for TiC and the values for the other standards are obtained from it by using this to scale the parameterisation of experimental data by Iakoubovskii et al [29].…”

“…Data are also taken over a range of thicknesses so that the effects of any surface layer can be removed. In this way, λ can be determined directly and compared to that obtained from the Iakoubovskii parameterisation [29].…”

Thin-Film Phase Plates for Transmission Electron Microscopy Fabricated from Metallic Glasses

“…[34]. The discrepancy between calculated and measured λ inelastic values can be explained because the Malis formula is only valid for small collection angles [35] and electron energies below 100 keV [36]. The probability for inelastic scattering in the PP-material can be calculated according to Eq.…”