Dislocation pile-ups in silicon

Abstract
Queues of dislocations with a common Burgers vector and, within the limits of resolution, a common slip plane have been observed in a deformed single crystal slice of silicon by means of the Lang technique. One such ‘pile-up’ is analysed in detail. The obstacle appears to consist of two Lomer dislocations which extend right across the crystal, but the configuration is partially relaxed since the leading dislocations are able, over part of their lengths, to pass the obstacle by cross-slip processes. It is believed that the glide dislocations are situated on at least two slip planes and that this accounts for their nearly uniform spacing.