Measurements of electron channeling pattern linewidths in silicon

Using a new method for improving the signal‐to‐noise of electron channeling pattern (ECP) contrast, preliminary quantitative measurements of the linewidths of ECP lines in silicon have been performed. The signal‐to‐noise was improved by utilizing a boxcar integrating circuit whose gating logic was referenced to the SEM horizontal scan signal. The measurements were done on the (220) series of reflections from 18 and 25 keV incident electrons by monitoring the specimen current as the SEM was scanning in the line mode. The measured linewidths are consistent with those predicted by the two beam theory of ECP intensity when the affects of the incident beam divergence, α, are accounted for. The appearance of ECP lines from very high order reflections is an indication that the limit of the reciprocal lattice vector, g, of a line that can be resolved in an ECP is limited more by the sample than by α. The finite α appears only to broaden the linewidths of higher order lines. These studies are being pursued to explore the potential of this technique for the study of crystalline perfection.