Defect states in plastically deformedn-type silicon

The electronic properties of deformed $n$-type silicon have been investigated via deep-level transient spectroscopy (DLTS). The four deformation-induced levels usually labeled in the literature as $A,$ $B,$ $C,$ and $D$ have been found. Their analysis as a function of the deformation parameters and the study of their thermal stability have allowed us to conclude that only the $C$ line, located 0.40 eV from the conduction-band edge, can be attributed to dislocations. The characteristics of this line are reported and discussed, taking advantage of the fact that, owing to the deformation conditions employed, it could be clearly resolved and analyzed in the spectra. The DLTS peaks have been simulated by the introduction of a broadening parameter, whose dependence on the dislocation density has been studied. Moreover, the capture kinetic of this line has been analyzed. The broadening of the observed DLTS peaks has been analyzed on the basis of two different physical mechanisms: crystal disorder and inhomogeneities in the Coulomb potential along the dislocation lines. A tentative identification of the defects responsible for the deep levels observed has been given.