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Quantitative Composition and Thickness Mapping With High Spatial Resolution By XEDS In a 300kv FEG-AEM

Published online by Cambridge University Press:  02 July 2020

M. Watanabe  and
D. B. Williams
M. Watanabe
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA, 18015, USA.
D. B. Williams
Affiliation:
Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA, 18015, USA.
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Extract

Since the first demonstration by Cosslett and Duncumb, X-ray mapping by an electron probe microanalyzer (EPMA) has become a most popular approach in microanalysis because elemental distributions of constituents in a bulk sample can be displayed visually. The major disadvantage of EPMA mapping is poor spatial resolution (∼ 1 μm). The spatial resolution of X-ray microanalysis can be improved to a few nanometers using electron transparent thin-specimens in the analytical electron microscope (AEM). However, X-ray count rates from thin specimens are strictly limited because of the improved spatial resolution (i.e. smaller interaction volume) and the poor collection efficiency of X-ray. To obtain reasonable counts for accurate quantification in the AEM, extraordinarily long mapping times are required. Therefore, quantitative X-ray mapping is rarely attempted in the AEM. However, these limitations can be overcome by use of intermediate-volt age instruments combined with field-emission guns to increase the beam current-density, careful stage design to maximize the X-ray collection efficiency and the peak-to-background ratio, and ultrahigh vacuum system to reduce contamination.

Type
Compositional Mapping With High Spatial Resolution
Information
Microscopy and Microanalysis , Volume 4 , Issue S2: Proceedings: Microscopy & Microanalysis '98, Microscopy Society of America 56th Annual Meeting, Microbeam Analysis Society 32nd Annual Meeting, Atlanta, Georgia July 12-16, 1998 , July 1998 , pp. 136 - 137
Copyright
Copyright © Microscopy Society of America

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References

1.Cosslett, V. E. and Duncumb, P., Nature, 177(1956)1172.CrossRefGoogle Scholar
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4. The authors acknowledge the support of Bettis Labs and Westinghouse. Special thanks to Prof. Z. Horita of Kyushu University for providing the Ni-Al-Mo specimens and Mr. D. W. Ackland of Lehigh University for helpful discussions and technical assistance.Google Scholar