The generation of shallow donors by annealing H-doped Czochralski crystals after electron irradiation was studied. The H was introduced by annealing at 1200C, in a H atmosphere, followed by quenching. The specimens were irradiated with 3MeV electrons. Three types of shallow donor, D1 to D3, were generated and annihilated during isochronal annealing between 300 and 650C; as revealed by measurements of the optical absorption at 6K. The generation of D1 could be described as being a first-order reaction. The activation energy for the generation of D1 was about 1.8eV. This value agreed well with the migration energy of a vacancy-O pair. It was therefore proposed that D1 was a complex of one VO pair and a H aggregate, and that neutral D1 was in a metastable state. The optical threshold energy for the excitation of the neutral charge state of D1 was about 0.36eV. The energy barrier between the neutral and stable states of D1 was estimated to be about 0.13eV.

Hydrogen-Oxygen-Vacancy Complexes in Czochralski-Grown Silicon Crystal. H.Hatakeyama, M.Suezawa: Journal of Applied Physics, 1997, 82[10], 4945-51