The relationship between the type of grown-in defect which was observed in Czochralski-grown crystals under various growth conditions and the ratio, V/G, of the growth rate to the temperature gradient in crystals was studied at temperatures near to the melting point of Si by performing global heat transfer calculations. It was found that the radius of the oxidation-induced stacking fault ring region was a function of V/G at the crystal center and did not depend upon the hot-zone structure of the Czochralski furnace or upon the axial position of the crystal. With decreasing V/G ratio, the oxidation-induced stacking fault region shrank and disappeared from the center of the crystal at a critical V/G value of about 13.2mm2/hC. In the case of V/G ratios which were larger than the critical value, vacancy-related grown-in defects such as infra-red light scattering defects and flow pattern defects were observed in the central region of crystals. In the case of V/G ratios which were smaller than the critical value, self interstitial-related dislocation clusters appeared. This relationship was shown to hold for most radial positions; except at about 30mm from the crystal edge, where out-diffusion of vacancies to the crystal surface was considered to explain the observed anomaly. It was concluded that the type of grown-in defect which appeared in Czochralski crystals, as well as in float-zone crystals, was governed by the V/G ratio.

M.Hourai, E.Kajita, T.Nagashima, H.Fujiwara, S.Umeno, S.Sadamitsu, S.Miki, T.Shigematsu: Materials Science Forum, 1995, 196-201, 1713-8