X-ray topographic studies of dislocation contrast in silicon after boron diffusion

The contrast of dislocations generated by boron diffusion in silicon is studied in detail. The anomalously narrow images observed from an array of emitter-edge dislocations are explained by considering the effect of the strain fields of neighbouring dislocations. Interactions between emitter-edge dislocations and dislocations inside the diffused region are described and a mechanism suggested. The existence of strong contrast from pure-edge dislocations when both g. b = 0 and g. b u = 0 leads to the conclusion that the emitter-edge dislocations are heavily decorated by precipitate. Burgers vector analysis of the dislocations inside the diffused region supports previous work on phosphorus-diffused silicon, and indicates that reactions have occurred between these dislocations. The unusual contrast of these dislocations is interpreted using Penning-Polder theory when surface effects are taken into account. Asymmetric reflection `area contrast' is observed from the diffused region.