Evolution of radiation-induced carbon-oxygen-related defects in silicon upon annealing: LVM studies

The evolution of carbon-oxygen-related defects upon isochronal annealing (75-325 degrees C in 25 degrees C steps for 30 min at each temperature) in electron irradiated Si crystals has been studied by means of local vibrational mode (LVM) spectroscopy. A complicated annealing behaviour of the LVMs related to the C4 (ICiOi) defect has been observed. At about 200 degrees C the bands at 940 and 1024 cm(-1) are transformed into three new LVM bands at 724 cm(-1) (O-related) and at 952 and 973 cm(-1) (both C-related). Further increase in annealing temperature up to 250-275 degrees C results in a transformation of the latter bands into a new set of LVM bands at 969 cm(-1) (O-related) and at 951 and 977 cm(-1) (both C-related). These bands disappear at about 300-325 C. It is suggested that all the above-mentioned LVMs arise from the C4 defect being in different configurations