Abstract
The observation of a variant of the Si E’ center which is possibly unique to thin films of SiO2 is reported. This center which has not been reported for bulk a‐SiO2 is detected after x irradiation of films grown on (111) and (100) wafers of silicon. The center contains two threefold coordinated Si atoms with one having axial symmetry and the other having orthorhombic symmetry. Evidence indicates that this defect is very near the Si‐SiO2 interface. The annealing behavior of the defect has a bias dependence which is very similar to that observed for fixed oxide charge in metal‐oxide‐semiconductor devices.