Correlations of vibrational frequencies with VO4 defect in irradiated silicon

This paper reports infrared spectroscopy studies on oxygen related defects in Czochralsky grown neutron irradiated Silicon material subsequently submitted to heat treatment. The sequential formation of various VO_n (n=1,2,3,4) defects according to the reaction process VO→VO₂→VO₃→VO₄ is investigated. We argue that on increasing the annealing temperature different sites for the addition of oxygen atoms become available, triggering for n>2 two parallel formation sequencies in relation with VO₃ and VO₄ defects. Thus in the first sequence the oxygen atoms are added in adjacent sites to VO₂ defect although in the second sequence the oxygen atoms are added in the same vacant site of VO₂ defect