It was demonstrated that at least 2 types of E' defect precursors existed in conventionally processed thermal SiO2 thin films. It was found that the capture cross-section of one type of defect exceeded that of the other type of defect by an order of magnitude. The former centers were also distributed far more widely throughout the oxide than were the other defects. The resonance of the former defect, unlike that of the latter defect, was not stable at room temperature.

J.F.Conley, P.M.Lenahan, H.L.Evans, R.K.Lowry, T.J.Morthorst: Applied Physics Letters, 1994, 65[18], 2281-3