Review—Ion Scattering as a Surface Analytical Tool for the Study of Passive Layers

Abstract

Among several surface analytical methods Ion Scattering is a possibility to study the composition and depth profile of passive layers. Examples are presented for Rutherford Backscattering Spectroscopy (RBS) for the investigation of thick oxide layers up to more than 100 nm on Al containing additions of other metals like Cu and low Energy Ion Scattering Spectroscopy (ISS or LEIS) for thin passive layers of a few nm thickness of binary alloys. The chemical structure of thin passive layers with a high depth resolution is obtained by ISS depth profiles, which supports the results for these films obtained by X-ray Photoelectron Spectroscopy (XPS). A reliable specimen preparation in an electrochemical cell attached to the UHV spectrometer, i.e. in a closed system is described, which helps to exclude changes and artifacts by unwanted environmental factors, which might affect the results of fundamental investigations.