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SIMS Time-of-Flight Surface Spectroscopy Surface Imaging Depth Profiling 3D Analysis Retrospective Analysis Secondary Ion Mass Spectrometry For SIMS (Secondary Ion Mass Spectrometry) analysis, a solid surface is bombarded by primary ions of some keV energy. The primary ion energy is transferred to target atoms via atomic collisions and a so-called collision cascade is generated. Part of the energy is transported back to the surface allowing surface atoms and molecular compounds to overcome the surface binding energy. The interaction of the collision cascade with surface molecules is soft enough to allow even large and non-volatile molecules with masses up to 10,000 u to escape without or with little fragmentation. Most of the emitted particles are neutral in charge, but a small proportion is also positively or negatively charged. The subsequent mass analysis of the emitted ions provides detailed information on the elemental and molecular composition of the surface. SIMS is a very surface sensitive technique because the emitted particles originate from the uppermost one or two monolayers. The dimensions of the collision cascade are rather small and the particles are emitted within an area of a few nm in diameter. Hence, SIMS can be used for micro analysis with very high lateral resolution, provided that such finely focused primary ion beams can be formed. SIMS is destructive in nature because particles are removed from the surface. This can be used to erode the solid in a controlled manner to obtain information on the in-depth distribution of elements. This dynamic SIMS mode is widely applied to analyze thin films, layer structures and dopant profiles. In order to receive chemical information on the original undamaged surface, the primary ion dose density must be kept low enough (< 1013 cm-2) to prevent a surface area from being hit more than once. This so-called static SIMS mode is widely used for the characterization of molecular surfaces. Most of the emitted particles are neutral in charge. Post-Ionization of these particles by electrons, plasma or photons allows mass analysis of these particles. This technique is called Secondary Neutral Mass Spectrometry, SNMS. One of the most efficient ways to ionize the emitted neutrals is Laser Post-Ionization (Laser-SNMS). This technique is becoming very attractive for the quantitative analysis of extremely small volumes.