Inhomogeneities in plastically deformed silicon single crystals. I. ESR and photo-ESR investigations ofp- andn-doped silicon

A quantitative analysis is given for three distinguishable effects contributing to inhomogeneities of the band gap of plastically deformed and doped silicon: (a) capture of charge from the chemical dopants to deep-point-like defects, (b) capture of the charge by deep defects in the core of dislocations, and (c) capture of the charge into states split off from the band edges that are caused by the presence of dislocations in the crystals. In crystals deformed below 700 ^∘{}C process (a) dominates and it gives rise to local shifts of the band edges. Contributions from processes (a) and (b) can be distinguished by only analyzing the ESR spectra of the deformed samples, but they do not lead to an accumulation of delocalized charge along the dislocations, which, in the case of process (c), is shown to be evident from the appearance of electric-dipole spin resonances. Observation of the last process requires special deformation procedures that produce straight dislocation segments.