The detailed correlation of surface morphology and subsurface microstructure has been made possible by the scanning transmission electron microscope. This instrument provides the capability for simultaneous and independent secondary electron and transmitted electron imaging from the same sample area. This includes the ability to generate mixed secondary/transmitted electron images, which form a concise visual presentation of the information in the two component images.
Correlative surface and through-volume specimen examination of this type has most frequently been applied to backthinned samples, which are specifically prepared in a way which produces electron-transparent material in the immediate vicinity of a surface of interest on the original bulk sample. However, the technique has also been found to be useful for relating local microstructural features to the overall structure of the sample, and for determining the local specimen geometry for microanalysis by energy dispersive x-ray spectrometry. The formation of a mixed secondary/transmitted electron image also serves as a novel means of signal processing which reduces the difficulty of forming a transmitted image from regions adjacent to the edges of a thin foil sample.
Allen, R. M.
"Secondary Electron Imaging in the Scanning Transmission Electron Microscope,"
Scanning Electron Microscopy: Vol. 1985
, Article 1.
Available at: https://digitalcommons.usu.edu/electron/vol1985/iss3/1