Dislocation microstructures in Si plastically deformed at RT

Dislocation microstructures induced by plastic deformation at room temperature in Si have been investigated by TEM. Plastic deformation has been obtained by using two types of technique: deformation under a confining pressure of 5 GPa in an anisotropic multi-anvil apparatus and by surface scratching. The TEM observations show common features in the two deformation substructures which are characteristic of high stress-low temperature deformation. The deformation microstructures are built with dislocations with alpha /2(110) Burgers vector in (111) planes which are undissociated. Such dislocations are mainly aligned along the screw orientation and (112) orientations at 30 degrees from the Burgers vectors as well as along (132) orientations at 41 degrees from the Burgers vector. The occurrence of those Peierls valleys confirms that different dislocation core configurations from those usually dealt with at higher temperatures have to be taken into account when dislocations are nucleated at very high stresses.