Influence of point defect concentration in growing Cz-Si on the formation temperature of the defects affecting gate oxide integrity

The defects affecting gate oxide integrity of Cz-Si form in a specific temperature range during crystal growth process. In order to understand the defect formation mechanism in the temperature range, we carried out annealing experiments to simulate the thermal history of the growing crystals using small blocks cut from the crystal ingots. We have found that the formation temperature is dependent on concentration of point defects, which are introduced (quenched) into the crystals by rapid cooling from high temperatures. The excess chemical potential which is related to supersaturation of the point defects, Delta mu, is Constant at the formation temperature. However, the formation temperature is not influenced by the oxygen content of the specimens from 8 to 10 x 10(17) cm(3). From these results, it is concluded that the agglomeration of the supersaturated point defects leads to the defect formation. The excess of the chemical potential Delta mu to cause the agglomeration is estimated to be about 18% of the formation energy of the point defects.