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Electron-Excited X-Ray Microanalysis at Low Beam Energy: Almost Always an Adventure!†

Published online by Cambridge University Press:  12 August 2016

Dale E. Newbury  and
Nicholas W.M. Ritchie
Dale E. Newbury*
Affiliation:
Materials Science Measurement Division, National Institutes of Standards and Technology, Gaithersburg, MD 20899, USA
Nicholas W.M. Ritchie
Affiliation:
Materials Science Measurement Division, National Institutes of Standards and Technology, Gaithersburg, MD 20899, USA
*
*Corresponding author.dale.newbury@nist.gov
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Abstract

Scanning electron microscopy with energy-dispersive spectrometry has been applied to the analysis of various materials at low-incident beam energies, E0≤5 keV, using peak fitting and following the measured standards/matrix corrections protocol embedded in the National Institute of Standards and Technology Desktop Spectrum Analyzer-II analytical software engine. Low beam energy analysis provides improved spatial resolution laterally and in-depth. The lower beam energy restricts the atomic shells that can be ionized, reducing the number of X-ray peak families available to the analyst. At E0=5 keV, all elements of the periodic table except H and He can be measured. As the beam energy is reduced below 5 keV, elements become inaccessible due to lack of excitation of useful characteristic X-ray peaks. The shallow sampling depth of low beam energy microanalysis makes the technique more sensitive to surface compositional modification due to formation of oxides and other reaction layers. Accurate and precise analysis is possible with the use of appropriate standards and by accumulating high count spectra of unknowns and standards (>1 million counts integrated from 0.1 keV to E0).

Keywords

DTSA-IIEDSmicroanalysisSEMX-ray
Type
Technique and Instrumentation Development
Information
Microscopy and Microanalysis , Volume 22 , Issue 4 , August 2016 , pp. 735 - 753
Copyright
© Microscopy Society of America 2016 

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Footnotes

†

Certain commercial equipment, instruments, or materials are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose.

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