Hydrogen-oxygen-vacancy complexes in Czochralski-grown silicon crystal

We studied the process of generation and some properties of shallow donors generated by annealing a hydrogen-doped Czochralski-grown silicon crystal after electron irradiation. Hydrogen was doped by annealing specimens at 1200 degrees C in hydrogen atmosphere followed by quenching. Specimens were irradiated with 3 MeV electrons. Three kinds of shallow donors, termed D1-D3, were generated and annihilated due to isochronal annealing between 300 and 650 degrees C as shown by the measurement of optical absorption at 6 K. The generation process of D1 was well described by the first order reaction. The activation energy for the generation of D1 was about 1.8 eV. This agreed well with the migration energy of a vacancy-oxygen pair (VO pair). Hence, it is proposed that D1 is a complex of one VO pair and a hydrogen aggregate. Neutral D1 is in a metastable state. The optical threshold energy for the excitation of the neutral charge state of D1 was about 0.36 eV. The energy barrier from the neutral to the stable state of D1 was estimated to be about 0.13 eV. (C) 1997 American Institute of Physics.