QUANTITATIVE SECONDARY NEUTRAL MASS-SPECTROSCOPY OF THIN-FILMS

A secondary ion mass spectrometer, having a liquid metal primary ion beam capable of focusing down to below 100 nm, has been adapted so that it can operate in conventional secondary ion or secondary neutral analysis mode. An electron beam is used to ionize the neutral species in the secondary neutral mass spectroscopy (SNMS) mode. Optimum operating conditions are reported including the use of an energy filter, which is shown to reduce background signals significantly. Typical results for various types of thin film coatings are reported including semiconductor materials, multilayer structures, metal oxides and metal alloys. A comparison of the SNMS data with that obtained in the secondary ion mass spectroscopy mode shows that the new technique provides more reliable quantitative data.