The peculiarities of formation and annealing, and energy level position of an Fe-vacancy (FeV) pair were investigated by using electron-spin resonance and photo-electron spin resonance methods. The pairs were created in Fe-doped float-zone grown samples during electron-irradiation and survived annealing at 400 to 500C. The results of a photo-electron spin resonance study suggested that FeV in Si was a hole trap with an energy level positioned at about 0.51eV above the valence band. The complexes of a vacancy and two Fe atoms (2FeV) were less stable than the FeV pairs and annealed out at 300 to 350C in the same samples.

Properties of an Iron-Vacancy Pair in Silicon. T.Mchedlidze, M.Suezawa: Japanese Journal of Applied Physics - 1, 2002, 41[12], 7288-92