We show that annealing of the buried oxide layer used for device isolation generates point defects in the SiO2film and that this defect generation is independent of temperature above 1000 °C. Electron paramagnetic resonance data obtained on thermally grown buried oxides and those fabricated by ion implantation indicate that the defect is intrinsic to the structure of SiO2and is associated with an oxygen deficient environment. The similarity in the generation of the defects studied here and the formation of SiO observed in earlier studies of low pressure high temperature oxidation suggests that the formation of the buried oxide defect is related to the reduction of SiO2and the release of SiO. ©1995 American Institute of Physics.