EXAMINATIONS REGARDING THE CORRECTNESS OF QUANTITATIVE SURFACE-ANALYSIS USING SNMS

For the assessment of the correctness of depth profile analyses with non-ideal technical metal surfaces using secondary neutral particle mass spectrometry (SNMS), the roughness of the sample surface was examined for the transition width of the signal. It is shown that with elements with low sputter rates (Al Mn), similar to that of the substrate element (Fe), there is no significant influence of the roughness. However, clear dependencies are observed for tin and zinc, elements with high sputter rates. Whereas tin gave acceptable results when the roughness was significant, cone formation was observed with zinc which caused abnormal sputter behaviour. The use of high-frequency sputter processes eliminates this cone formation and leads to constant signals, even with thick zinc layers. This method is therefore not only suitable for use with non-conductors, as originally planned, but also offers considerable advantages in the analysis of metal coatings.