Dislocation dissociation widths in silicon at low temperature under controlled high-stress orientations

Abstract

Abstract Dissociation widths of dislocations in silicon submitted to high stress and low temperature (HS/LT) are reported. In the first part of the paper, force systems (glide and climb components) acting on a pre-existing dissociated dislocation loop are analysed in terms of the deformation compression axis K. Then two main force systems are experimentally examined: (i) static cases for which the whole dislocation is at rest while partials are submitted to forces with directions which should result in a narrowing or a widening of the stacking fault ribbon; and (ii) dynamic cases (K = 〈120〉) with very different force systems. In all cases stacking faults have been found to be intrinsic. Climb forces seem to act on friction forces of 30[ddot] partials according as to whether they are positive or negative. Models developed by Alexander to explain the mobility of dislocations in the HS/LT conditions cannot account for our results. It is suggested that point defects could have an important effect on the mobility of partials.