New powerful tool for material characterisation
Published: 20 April 2015 - Marianne Evans
HORIBA Scientific novel Plasma Profiling TOFMS (PP-TOFMS) instrument provides the chemical composition as a function of depth of solid materials. This depth profiling technique consists of a glow discharge plasma source that erodes and ionises sample material coupled to an ultra fast time of flight mass spectrometer.
High-throughput and universal depth profiling tool
The high ionic density of the glow discharge plasma results in a high sputtering rate. In addition the pre-analysis time is very much reduced as sample does not need to be transferred to a high vacuum chamber. As a result, sub-micron thin films can be analysed in a few minutes.
The use of a radio frequency excitation signal allows analysis of all types of materials ranging from conductive to non-conductive (e.g. thin films on thick glass substrates) and from inorganic to hybrid. A quick sample preparation permits the analysis of coatings on flexible substrates.
High dynamic range
Mass Spectrometry coupled to a high intensity plasma source results in a highly sensitive technique. A 106 dynamic range is reached at the nanometer depth scale. In-depth or bulk measurements allow to reach sub ppm sensitivity. In addition, thanks to the separation of sputtering and ionization (low matrix effects), a simple internal calibration calculation results in semi-quantitativeresults (atomic concentrations in the correct order of magnitude).
Full mass coverage
The great advantage of a time of flight mass analyser is its capability of recording complete and continuous mass spectra. PP-TOFMS measures a mass spectrum covering all elements of the periodic table every 33 µs. Any element can thus be monitored as a function of erosion time/depth. This means not only zero risk for missing any elemental depth variation but also full probability of detecting the presence of unexpected elements (contamination). Finally all isotopes are recorded, which can be useful in case of isobaric interferences and for studying mechanisms (oxidation, diffusion) through the use of isotopic labeling.