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 °C in 25 °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 °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 °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.