The effects of fast neutron irradiation upon oxygen atoms in Czochralski silicon were investigated systemically using Fourier transform infra-red spectrometry and positron annihilation. Using isochronal annealing, it was found that the variations in interstitial oxygen concentration in fast-neutron irradiated Czochralski silicon fluctuated widely with increasing temperature: especially between 500 and 700C. When the Czochralski silicon was annealed at 600C, the V4 appearing as three-dimensional vacancy clusters caused the formation of molecule-like oxygen clusters. These dimmers, with small binding energies (0.1 to 1.0eV), could diffuse into the Si lattices more easily than could single oxygen atoms, thus leading to marked oxygen agglomerations. When the Czochralski silicon was annealed at up to 700C, the three-dimensional vacancy clusters disappeared and the oxygen agglomerations decomposed into single oxygen atoms.

The Effects of Fast Neutron Irradiation on Oxygen in Czochralski Silicon. G.F.Chen, W.B.Yan, H.J.Chen, X.H.Li, Y.X.Li: Chinese Physics B, 2009, 18, 293