The vacancy formation energy in Czochralski-grown Si crystals was determined by applying a new quenching method. In this method, the optical absorption due to hydrogen atoms bound to vacancies was measured to estimate the vacancy concentration. In contrast with floating-zone grown Si crystals, one more optical absorption peak other than 2223/cm peak was observed at about 2120/cm. The defects responsible for the 2120/cm peak were proposed to be VOH4 and VO2H4, inferring from the Voronkov-Falster model on grown-in defects in Czochralski crystals. The vacancy formation energy estimated from the quenching temperature dependence of the integrated intensity of the 2120/cm peak was about 2.3eV. After taking the contribution from vacancies generated in the perfect crystal part into account, the formation energy was determined to be approximately 1.5eV. Such small formation energy compared to that (3.85eV) in high-purity crystals was thought to be due to a strong interaction between a vacancy and an oxygen atom.

Vacancy Formation Energy in Czochralski-Grown Si Crystals Determined by a Quenching Method. M.Suezawa, N.Fukata, J.Vanhellemont, I.Yonenaga: Journal of Applied Physics, 2011, 110[8], 083531