The COV defect in neutron irradiated silicon: An infrared spectroscopy study

We report infrared (IR) spectroscopy studies on defects in carbon containing neutron irradiated Czochralski grown silicon (Cz-Si). Prior to irradiation the material was subjected to high temperature treatments (HT) at 1000 °C. Two weak bands at 842 and 852 cm−1 were mainly investigated. It was found that their intensity depends on the oxygen and carbon content of Si. Additionally, the bands exhibit an annealing behavior similar to that of the 3942 cm−1 optical band of the carbon-oxygen-vacancy (COV) complex, previously reported in electron irradiated Si. Semi-empirical calculations of the local vibration mode (LVM) frequencies of a proposed structure of the COV complex are in very good agreement with our experimental data. These findings led us to assign the pair of bands at 842 and 852 cm−1 to the COV defect.