Limitations of ion etching for interface analysis

The limitations of using ion sputtering for interfacial analysis are reviewed. It is concluded that many artifacts may degrade interfacial resolution—surface roughness, zone of mixing, bulk and surface diffusion, implantation, residual gas adsorption and matrix effects. Techniques to minimize these limitations are suggested. Some examples are: use of reactive ion beams, multiple ion beams, sample rotation and special mounting, varying the ion energy and incidence angle, and deconvolution. It is concluded, however, that sputtering may destroy atomic arrangement and chemical state information at the interface, and new approaches are needed to determine these interfacial parameters.