Chemical depth profiling analysis of optical coatings require (a) qualification for accurate measurement of the composition of the major elements as well as any dopants or impurities (b) high sensitivity for detection and measurement of ultra low levels of the dopants or impurities and (c) good depth resolution in depth profiling applications for resolving very thin layers or the distribution of various elements within the layers. This paper will first provide an overview of the various microprobe surface analysis techniques for chemical analysis of thin films and compare their relative merits and limitations in terms of sensitivity and quantification. It will then outline the principles a relatively new technique, Sputtered Neutral Mass Spectrometry (SNMS), and discuss its merits for quantitative depth profiling analysis of a wide range of optical coatings.
