Time of Flight Secondary Ion Mass Spectrometry

Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is a surface characterization, micro-analysis technique which is based upon the liberation and identification of ions that are sputtered from a sample’s surface. This method is extremely surface sensitive since most of the liberated material comes from the top-most surface layers, yet it also has the capability to selectively etch away material and perform in-depth analyses. The data provide molecular and elemental information about a wide variety of materials.

With this technique, the sample surface is interrogated with a pulsed beam of high energy primary ions. These ions have sufficient energy to both sputter and ionize atoms and molecules in the surface at and near the ion impact location. The newly formed secondary ions are accelerated into an analyzer where they are separated according to their mass-to-charge ratios. The mass-to-charge ratio is used to identify the elemental and chemical species present in the sample. Molecular fragmentation patterns and isotope ratios aid in the identification of many species in complex matrices. Two and three dimensional elemental and molecular maps can be generated with sub-micron spatial resolution.