CONTRAST AND RESOLUTION OF SEM CHARGE-COLLECTION IMAGES OF DISLOCATIONS

Image profiles obtained in the scanning electron microscope operating in the charge-collection mode are calculated for a dislocation perpendicular to a surface barrier. The image resolution is not limited by the minority-carrier diffusion length in the semiconductor, but only determined by the generation volume, in agreement with experiment. The contrast characteristics of a dislocation differ from those of a localized defect, leading to a practical method for distinguishing the two types of imperfections.