Direct Imaging of Trace Elements, Isotopes, and Molecules Using Mass Spectrometry

Abstract

Secondary ion mass spectrometry (SIMS) is based upon the energetic ion bombardment of surfaces resulting in in the emission of sputtered particles, including both atomic and molecular ions. The use of mass spectrometric detection provides a highly versatile and sensitive tool for surface and thin film microanalysis. The scope of the technique includes a diversity of analysis modes including:1.Elemental Depth Profiling (dynamic SIMS),2.Laterally Resolved Imaging (ion microprobe or ion microscope analysis),3.Image Depth Profiling (combination of modes 1 and 2 providing 3-D images),4.Molecular Monolayer Analysis and Imaging (static SIMS),5.Sputtered Neutral Mass Spectrometry (post-ionization).Much of the early work in dynamic SIMS centered on depth profiling and imaging techniques, with an emphasis on applications to electronic materials. SIMS has made extensive contributions to semiconductor materials science since the 1960's, including the development of new devices and processes, and in failure analysis.