Development and production of industrial materials often requires identification of unexpected and/or unknown components (e.g. contaminants, interaction products, …) at the molecular level. TOF-S-SIMS is one of the few nano-analytical methods which offers a remarkable wealth of structural information.
Secondary ion mass spectra are acquired with a TOF-SIMS IV (ION-TOF, Germany, Münster) equipped with a 25 keV Bi3+ primary ion gun. Ions are extracted from a surface region of maximum 500 µm x 500 µm in the so-called “high current bunched mode” which is optimised for the best mass resolution.
A mass resolution of 5000 (FWHM on Si+ peak) is obtained and because mass spectra can become very complex by the superposition of many components, this mass resolution is decent for the deductive identification of different components. The ion assignment is supported by a mass accuracy that is better than 100 ppm.