ATOMIC AND ELECTRONIC Z-CONTRAST EFFECTS IN HIGH-RESOLUTION IMAGING

At relatively large scattering angles, Z-dependent effects occur in bo th the atomic (elastic or quasi-elastic) electron scattering and in th e inelastic electron-electron scattering and can thus exhibit chemical contrast at high spatial resolution. Results are shown for secondary electron imaging of semiconductor multilayers in both bulk specimens a nd in transmission specimens. Variations in electron-electron scatteri ng or stopping power can contribute to ADF images in the STEM and it m ay be useful to apply energy filtering as well as energy selection in their collection.