The formation energy and thermal equilibrium concentration of vacancies in Ge doped Czochralski-grown Si were studied by quenching of samples annealed at temperatures between 1200 and 1350 C for 1h under hydrogen atmosphere. After quenching, the majority of the formed vacancy and hydrogen containing point defect clusters were transformed into VH4 defects by a 1h anneal at 450C. Measuring the amplitude of the vibrational band of VH4 at 2223/cm as function of the quenching temperature permitted the estimation of the vacancy formation energy. An apparent formation energy of about 2eV was obtained for Ge doping between 7 x 1017 and 6.5 x 1020/cm3 which was significantly lower than the 4eV obtained for high purity Si. In the whole quenching temperature window, the vacancy thermal equilibrium concentration was significantly higher than in Si without Ge doping. It was shown that this lower apparent formation energy could be explained by the presence of vacancy traps.

On the Impact of Germanium Doping on the Vacancy Formation Energy in Czochralski-Grown Silicon. J.Vanhellemont, M.Suezawa, I.Yonenaga: Journal of Applied Physics, 2010, 108[1], 016105