Dislocation multiplication during the very first stages of plastic deformation in silicon observed by X-ray topography

The first stages of plastic deformation of FZ silicon single crystals were investigated by in situ X-ray topography at the ESRF, in creep conditions at temperatures between 975 and 1075 K, and for applied stresses from 22 to 44 MPa. A special attention was given to dislocation multiplication, and several features relevant for this phenomenon were observed: cross slip at the surface or in the bulk of the specimen, instabilities in slip bands resulting from a non planar development of dislocations, creation of new sources by moving dislocations.