The use of a phi(rhoz) model for simultaneous determination of composition and thickness in analytical transmission electron microscopy
X-ray microanalysis using transmission electron microscopy (TEM) offers the possibility to perform quantitative analysis with high spatial resolution. Disadvantages are its low accuracy and the problem of preparing very thin specimens and the thin film standards, needed for the analysis and calibration. To calculate composition from the measured X-ray intensities, a peak-ratio method is usually applied, based on the thin film method by Cliff and Lorimer (Proceedings of the Fifth European Congress on Electron Microscopy, 1972, p. 140). We however, applied an entirely different approach, calculating the composition using a full matrix correction method based upon a phi(rhoz) matrix correction model as they are commonly used in EPMA measurements up to 40 kV. The validity of the model under TEM conditions was checked by performing bulk analyses on AlNi and AlTi samples and thin film analyses on an AlNi TEM specimen. In principle, both thin and thick specimens as well as light elements can be analysed this way. No major changes to the TEM set-up or simplifications to the model are needed, only an accurate beam current meter is required.
Boon
G
Bastin
GF