Atomic and molecular information with high sensitivity
Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is an analytical method for the chemical characterization of solid surfaces. The method captures both the atomic and molecular composition of the top 1-3 monolayers and can be used on both conductive and insulating surfaces. With detection limits in the ppm range, even small amounts of a substance can be detected sensitively.
Details on ToF-SIMS
Chemical screening of surfaces
Secondary ion mass spectrometry (ToF-SIMS) can be used to determine the atomic and molecular composition in the top 1-3 monolayers of a solid (static SIMS). The sample surface is bombarded with charged particles (ions) with energies of up to 30 keV. The masses of the secondary ions that are emitted from the surface as a result of this are determined. Elements and molecules can be detected simultaneously (in parallel). The use of Time-of-Flight analyzers for mass detection leads to a high detection sensitivity (ppb, fmol). Quantification of the data requires the use of suitable standard samples. Semi-quantitative data can be obtained if the samples to be compared have a similar basic chemical composition.
Beside mass spectra, images can be recorded where a lateral resolution of 300 nm is routinely achieved. By a continuous ion bombardment, a sample can also be removed step by step (ion sputtering, depth profiling, sputtering, dynamic SIMS). In this way, element information is captured as a function of depth. Modern instruments enable the recording of depth profiles of both inorganic and molecular layer structures. By combining imaging with depth profiling it is possible to image and analyze the three-dimensional structure of a solid (3D micro-analysis).
The requirements for the sample preparation are minimal. In most cases, the samples can be examined without further pretreatment. However, the material must be vacuum compatible. In addition to solids, it is also possible to analyze powders or liquids.