Scanning Electron Microscopy


The Sputtered Thermal Ion Mass Spectrometry method (STIMS) consists of collecting a part of the matter sputtered from a solid by ion bombardment into a heated cell where it is reduced into atoms. A thermal ionization process or an electron impact process taking place in the cell yields ions which are extracted and mass analyzed. The composition of the solid is determined from ion intensities after calibration of ionization coefficients. It has been demonstrated that the method has an absolute quantitative character. Applications to elemental quantitative analysis (identification of new compounds in diffusion couples, dust particle analysis) and in-depth analysis of thin layers (unannealed, annealed and amorphous layers) are being developed. We have found that in-depth resolution is better in annealed layers than in unannealed ones, it can be improved by lowering the primary ion energy below 2 keV and it is very good in amorphous materials.

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