The effects of annealing p-type material in a Cu-contaminated ambient were analyzed by using transmission electron microscopic and electron beam-induced current methods. Experiments were performed on Czochralski and float-zone polish-etched samples which had been thermally oxidized, or annealed in vacuum. Dislocation nets which were decorated with Cu were formed by oxidation; thus leading to electrically active cruciform extended defects. The density of nucleation sites was lower in oxidized float-zone material, due to the absence of O precipitates. When float-zone material was annealed in a vacuum, small Cu platelets formed; thus showing that the concentration of Si interstitials, injected during oxidation, probably played a role in the precipitation of Cu in Si.

A.Correia, A.Boutry-Forveille, D.Ballutaud: Solid State Phenomena, 1996, 47-48, 353-8