Scanning electron microscope image contrast was investigated for dislocations in semiconductor and metallic materials. It was revealed that single dislocations could be observed with high contrast in scanning electron microscopic images formed by back-scattered electrons in the normal configuration for scanning electron microscopy. The back-scattered electron images of dislocations were compared with those of the transmission electron microscope and scanning transmission electron microscope and the dependence of back-scattered electron image contrast upon the tilting of specimen was used to examine the origin of image contrast. From the experimental results, it was concluded that the back-scattered electron images of single dislocations were attributable to the diffraction effect and related to high-angle dark-field images of scanning transmission electron microscopy. Scanning electron microscopic observations were made of single dislocations in nitride semiconductors and metal materials and it was concluded that single dislocations were observed with a high contrast in BSE images with an AsB detector under normal configuration conditions for scanning electron microscopy. For a bulk specimen, the image contrast of dislocations became high at 8 to 17kV. The strong dependence of dislocation contrast upon the tilt of the specimen was thought to be due to the diffraction effect. Mutual similarity in image contrasts was recognized between scanning electron microscope BSE images and STEM DF images. This suggested that the image contrasts could be considered in the same context.

Scanning Electron Microscope Observation of Dislocations in Semiconductor and Metal Materials. N.Kuwano, M.Itakura, Y.Nagatomo, S.Tachibana: Journal of Electron Microscopy, 2010, 59[1], S175-81