Defect states in plastically deformed p-type silicon crystals investigated by the Hall effect

Measurements of Hall effect and dc conductivity have been conducted on plastically deformed p-type floating-zone-grown silicon crystals to investigate the energy levels of defects introduced by deformation. The temperature dependence of the carrier concentration is analyzed on the basis of the model in which electrically active centers induced by deformation are assumed to be distributed discretely in the crystal. It is shown that both acceptors and donors having deep energy levels are introduced simultaneously by deformation, the concentrations of which are proportional to the dislocation density. The concentration of the deformation-induced acceptors is found to be 6–7 times as high as that of the deformation-induced donors. The energy levels of these acceptors and donors are approximately at the same position, namely, 0.3–0.4 eV above the top of the valence band.