High-brightness liquid metal ion sources (LMIS) allow SIMS microprobe analysis with 50 nm spatial resolution at current densities > 1A/cm2. Chemical imaging of matrix and trace elements on the submicron scale is now achieved using a digital image storage system allowing picture processing and direct comparison of SEM and SIMS images using colour overlays. While high-sensitivity quadrupole mass spectrometers have been developed for SIMS imaging. the ultimate in sensitivity requires magnetic or time-of-flight mass spectrometers
