Characterization of thin film materials by 400 kV electron microscope images and with an energy filter

Characterization of thin film materials by the contrast of high resolution electron microscope images and by the images of electrons that excite the core electrons of the specimen is discussed. Using current high resolution electron micrographs, which are produced by partially coherent waves, the best focus for obtaining the atomic structure images of three crystals, MgO/MgAl2O4/Al2O3, has been found using pseudo AFF conditions. Three kinds of electron microscope images of ThO2 crystal, formed by the zero-loss, plasma-loss and O-4,O-5 core-loss electrons, are shown. Three similar images of a Si crystal, which precipitated in an Al crystal, are also shown, and the contrast mechanism of core-loss electron images is discussed by deriving the inelastic scattering factors of Si and Al crystals and using multi-slice elastic image contrast calculations. It is noted that the individual spot contrast in Si core-loss images of a small crystal is due to the images of Si atoms in a single atomic column when the thickness is less than 10 nm.