The weak-beam method of electron microscopy was used to investigate the dissociation of dislocations. Total dislocations with (a/2)<110> Burgers vectors were found to be dissociated into Shockley partial dislocations, with a separation of 7.5nm for a pure edge orientation and 4.1nm for a pure screw orientation. The intrinsic stacking-fault energy, calculated from the measured dissociation width using anisotropic elasticity theory, was 51mJ/m2. The method was also used to image partial dislocations at threefold dislocation nodes. All nodes in the specimens examined were found to be extended, and of about the same size; indicating that the intrinsic and extrinsic stacking-fault energies were comparable. Measurements of the radii of curvature of partial dislocations at the nodes gave a value of 50mJ/m2 for the intrinsic stacking fault energy.

The Dissociation of Dislocations in Silicon. I.L.F.Ray, D.J.H.Cockayne: Proceedings of the Royal Society A, 1971, 325[1563], 543-54