The effect of heat treatment conditions and point defects on oxygen precipitation was investigated with various grown-in defect region wafers. The behavior of oxygen precipitation depends oil the nucleation temperature and the type and the concentration of point defects. The peak temperature of nucleation for oxygen precipitation is 687-734degreesC in vacancy-rich, oxidation-induced stacking fault ring, interstitial Si-rich and interstitial pure regions. In vacancy-pure region, the peak temperature of nucleation is about 870degreesC. The vacancy plays an important role in increasing the peak temperature of nucleation for oxygen precipitation. (C) 2002 Elsevier Science B.V. All rights reserved.