Depth-resolved analysis of local atomic structures via X-ray absorption spectroscopy through the detection of energy-loss Auger electrons

Abstract

Auger electrons are generated in a solid lose energy because of inelastic scattering, and the amount of energy loss depends on the distance traveled. These electrons are emitted from a sample surface with various energies depending on the generation depth. An electron analyzer was used to detect energy-loss Auger electrons from a copper plate with a thickness-defined oxide film (39 mm), and extended X-ray absorption fine structure (EXAFS) spectra according to the depth were successfully obtained. The results demonstrate that performing depth-resolved analysis of local atomic structures using Fourier transformation of EXAFS oscillations is now possible (e.g., up to ∼ 120 nm for Cu). The maximum analysis depth exceeds the value in total electron yield, a common measurement mode, by a factor of about 2.