Development of a ToF version of the desktop MiniSIMS utilising a continuous primary ion beam

Abstract

The Millbrook MiniSIMS remains a unique concept in SIMS instrumentation. An upgraded version of the MiniSIMS based on a time-of-flight (ToF) mass spectrometer has now been developed. Unlike the vast majority of ToFSIMS instruments, the ToF MiniSIMS uses a continuous primary ion beam and a pulsed secondary ion beam. The instrument has the usual ToF attributes of parallel mass detection, extended mass range and higher mass resolution, but also features a high duty cycle. The result is very fast data acquisition, especially in imaging mode. Moreover, in depth profiling, a continuous beam allows all sputtered material to contribute to the analysis by eliminating the requirement for cycling between etching and analysis modes. The combination of a ToF spectrometer and a continuous primary beam is thus ideally suited to the MiniSIMS concept of a high-throughput instrument able to acquire spectra, images and depth profiles. The higher performance opens up new applications for the MiniSIMS instrument in the identification of organic materials and small area analysis, especially for materials with largely unknown composition or depth distribution.