Buried amorphous-layer impact on dislocation densities in silicon

The impact of amorphous layers on dislocation densities in silicon piezo-resistors was investigated by means of transmission electron microscopy and chemical etching. Mechanical bevel polishing at a shallow angle and selective etching were applied to assess the dislocation depth distributions. It was found that, despite the presence of additional defects after recrystallization, the initial presence of a buried amorphous layer reduced, after annealing, the dislocation density in the depletion region of a p-n junction, compared with the case of a shallower, surface amorphous layer.