Present State of TEM-SXES Analysis and its Application to SEM aiming Chemical Analysis of Bulk Materials

X-ray emission spectroscopy is widely used as a practical tool for compositional analysis of local specimen area and elemental mapping analysis in electron microscopes. X-rays with energy more than a few keV are dominantly due to electronic transitions between inner-shell electron levels. Those characteristic X-ray energies are useful for assignment of elements. On the other hand, X-rays originate form electronic transitions from valence bands (VB, bonding electron states) to inner-shell electron levels inform us energy states of bonding electrons. The energy of this latter X-ray ranges in ultrasoft or soft X-ray region form about 0.01 to a few keV. Since K-emissions of light elements and L-emissions of 3d transition elements are in this energy region, soft X-ray emission spectroscopy (SXES) based on electron microscopy (EM) can be a sensitive tool for elemental and chemical identifications. Thus, various applications are expected through this approach. We have developed and tested the SXES instruments by attaching to TEM, EPMA, and SEM. The spectrometers have an energy range of 504000eV by using four varied-line-spacing (aberration corrected) gratings [1,2,3]. This SXES spectrometer informs us energy states of VB from specified specimen areas in electron microscopy, which is hardly obtained by EELS and EDS.