Three-dimensional compositional mapping using ion microscopy and volume-rendering techniques

Abstract

Secondary ion mass spectrometry (SIMS), using ion microprobe or microscope instrumentation, couples lateral imaging and dynamic ion beam sputtering to provide 3-D compositional maps (image depth profiles). A data set acquired with an ion microscope may involve more than 100 massresolved ion images, each containing at least 64,000 pixels, with typical lateral and depth resolutions of 1 μm and 10 nm, respectively. The vast majority of prior quantitative surface analysis studies have addressed depth profiling, thin film, or overlayer measurements without the additional feature of laterally resolved imaging. The ability to create 3-D compositional maps using SIMS creates enormous challenges for quantification. In principle, each volume element requires individual calibration reflecting the combined effects of spatial resolution, sample heterogeneity, and variations in instrumental response. An overview of analytical considerations will be presented involving aspects of data acquisition, display, and processing, with a special emphasis on sector field mass spectrometers that provide high dynamic range image depth profiles.