SURFACE-ANALYSIS BY SECONDARY-ION MASS-SPECTROMETRY (SIMS)

Static secondary ion mass spectrometry (static SIMS) supplies detailed information on the atomic and molecular composition of the uppermost monolayer of a solid. This information is obtained by mass analysis of sputtered secondary ions emitted from this layer during keV primary ion bombardment. Damage to the uppermost monolayer is minimized by applying extremely low primary ion fluences. Progress in static SIMS over the past 30 years is described by following the most important developments in instrumentation, i.e. the introduction of single-ion counting techniques, quadrupole and time-of-flight mass analyzers, charge compensation devices, focused ion beams for imaging, UV laser postionization of sputtered neutrals and the on-line combination of SIMS with other devices for surface modification and analysis. Today, static SIMS allows high performance surface analysis of samples of any material, geometry and conductivity. In particular the atomic and molecular composition of real world samples, very often insulators and covered by complex mixtures of atomic and molecular surface components, can be obtained with high sensitivity and high lateral resolution. Present day applications of static SIMS include microelectronics, catalysis and polymer research as well as clinical analysis, environmental monitoring and all kinds of microstructure technologies. Fundamental research, in particular on the mechanism of molecular ion formation, is still in its very beginning.