It was recalled that the defects which affected gate oxide integrity in Czochralski-type material formed within a specific temperature range during crystal growth. In order to understand the defect formation mechanism in this temperature range, annealing experiments were used to simulate the thermal history of growing crystals by using small blocks which had been cut from crystal ingots. It was found that the formation temperature depended upon the concentration of point defects which was quenched into the crystals by rapid cooling from high temperatures. The excess chemical potential, which was related to the supersaturation of the point defects, was constant at the formation temperature. However, the formation temperature was not affected by O contents of between 8 x 1017 and 1018/cm3. It was concluded that the agglomeration of supersaturated point defects led to defect formation. The excess of chemical potential which was required to cause agglomeration was estimated to be equal to about 18% of the formation energy of the point defects.

T.Iwasaki, H.Harada, H.Haga: Materials Science Forum, 1995, 196-201, 1731-6