Computer simulation of SEM electron beam induced current images of dislocations and stacking faults

Abstract

Images of dislocations and stacking faults as obtained in the scanning electron microscope operating in the electron beam induced current (EBIC) mode are produced by computer simulation on a cathode ray tube plotter. The calculations are based on a model describing charge-collection by a surface barrier in presence of a defect and assume that the minority-carrier diffusion length L in the bulk semiconductor is infinite. It is shown that the approximation L=∞ is valid when L≫Rp (Rp is the range of the electron beam) and is suitable for studying the EBIC images of defects in silicon. Simulations of dislocation images illustrate the influence of the inclination angle of a dislocation with respect to the surface on the shape of its EBIC image. Computed images of stacking faults in (100) and (111) Si are used to investigate the dependence of the contrast distribution of the image on the energy of the electron beam. Comparison with some experimental micrographs indicates that the model gives a satisfactory description of observed images. Limitations and possible improvements of the model are also discussed.