Defects in phosphorus-doped float-zone silicon single crystals plastically deformed at 800C were studied by using the positron lifetime technique. The lifetime measurements were performed for the undeformed, as-deformed and all annealed samples at 20 to 300K. Three kinds of defect, including vacancy clusters, dislocation-bound vacancies and undisturbed dislocations were induced by deformation. It was proposed that the dislocation could be charged and this was well proved by fitting the experimental positron lifetime with all possible positron trapping models. The fitted results indicated that during the annealing process dislocation-bound vacancies were quite stable and they could not be annealed out until a thermal treatment at 1300C, when the negatively charged dislocation acted as shallow positron traps which influenced significantly the measured average positron lifetime. The density of the dislocation line decreased inconspicuously below the annealing temperature of 1000C, and the transition rate between the related defects of the dislocation line and vacancies was almost constant.

Thermal Stability of Defects in Plastically Deformed Silicon Studied by Positron Lifetime Spectroscopy. J.B.Pang, H.S.Leipner, R.Krause-Rehberg, Z.Wang, K.Zhou, H.Li: Semiconductor Science and Technology, 2012, 27[3], 035023