THE FORMATION OF HEXAGONAL SILICON AT TWIN INTERSECTIONS

It has been postulated that the formation of hexagonal Si in the deformation zone is related to multiple twinning, and a detailed crystallographic model for this transformation has been proposed. One feature of this model is the hypothesis that under strict plane strain conditions the region of twin intersection will be forced into hcp stacking in order to accommodate the strain of the crossing twin. While the observed crystallography of the hexagonal phase is in excellent agreement with this model, no direct evidence for this mechanism has been observed to date. This note reports such an observation by high resolution electron microscopy.