SIMS DEPTH PROFILE ANALYSIS USING MCS+ MOLECULAR-IONS

The use of Cs+ primary ions in conjunction with the detection of MCs+ molecular ions (where M is the element to be monitored) in SIMS depth profiling is shown to be an efficient method of minimizing the variations of ion yields with sample composition, e.g., at the interface of multilayer structures. Depth profiles of several such samples demonstrate that MCs+ intensities follow closely the concentrations of the respective elements, providing the possibility of a (semi) quantitative analysis of major components by means of secondary ion mass spectrometry. As indicated by the similarity of their energy distribution data, the formation and emission process of MCs+ molecules seems coupled to that of Cs+ ions.