Depth Profiling

Abstract

Each of the most commonly used surface characterization techniques, including Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy, ion scattering spectroscopy (ISS), ultraviolet photoelectron spectroscopy, secondary ion mass spectrometry, electron energy loss spectroscopy, and others, probe a given distance into a solid. ISS is exceptional in that it examines only the outermost atomic layer of a solid. The layer contribution to the total signal is quite different for these two experimental configurations, indicating that depth profiling over the outermost 15 to 30 atomic layers can be accomplished with AES by varying the incidence and collection angles, provided that the compositional distributions can be determined from the angle-resolved spectra. The bulk-sensitive distribution is essentially that obtained by performing AES in the conventional configuration. Depth profiling is a standard technique used in surface science. Depth profiling by ion sputtering provides the most viable means of obtaining subsurface compositional information.