Compositional Depth Profiling

Summary

It is possible to use both X‐ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) to provide compositional information as a function of depth, although they are essentially methods of surface analysis. The choice of method depends largely upon the required depth of analysis or the thickness of the layers being analysed. Although the non‐destructive methods are extremely useful for assessing compositional changes in the near surface region of the material, to obtain data from depths greater than this it is necessary to remove material by ion bombardment within the spectrometer. To analyse to greater depths than is practical using sputtering, it is necessary to resort to a process which removes material before beginning the analysis. Material removal can be achieved using a finely focused gallium ion beam, or by using two mechanical methods such as angle lapping and ball cratering.