Time-of-Flight Secondary Ion Mass Spectrometry Application to the Study of Surface Modifications

摘要

This paper gives an overview on the Time-of-Flight Secondary Ion Mass Spectrometry (T-of-SIMS) technique and its application fields. The static mode of the SIMS technique has been proposed a few years ago as a valuable tool for the surface analysis of organic materials. The sputtering processes involved in this low ion dose regime allow the emission of molecular ions (parents and fragments) whose mass analysis provides fingerprint mass spectra of all the species present at the topmost surface (about 1 nm). In addition to the conventional SIMS peculiarities, the coupling with a time-of-flight analyser provides a higher sensitivity, a high mass resolution and the access to theoretically unlimited mass range. The use of micro-focused (diameter < 0.2μm) liquid metal ion sources, rastered over the sample surface, gives also imaging capabilities to this technique. Finally, insulating samples can be analysed by using a pulsed beam of low energy electrons for charge buildup compensation. All these features make T-of-SIMS a very promising technique for all analytical problems related to the processing and the characterization of materials surface. Examples will be given in various fields: adsorption of organic molecules on various substrates, characterisation of surface modified polymers and metals for improved adhesion performance, and contamination of semiconducting devices.