It was noted that E′ centers in crystalline and amorphous SiO2 were first identified in 1956, when electron paramagnetic resonance was first used to study radiation-induced defects in quartz. Since then the primary defect responsible for the E′ family of electron paramagnetic resonance signals had been identified as being a positively charged O vacancy with asymmetrical relaxations of the 2 neighboring Si atoms. In the last 15 years, two E′ centers, known as Eγ’ and Eδ’ were found to play a key role in the dynamics of charged trapped caused by irradiation in Si metal–oxide–semiconductor structures. Here, a brief review was presented of E′ centers, and recent theoretical results that had elucidated many experimental observations in metal–oxide–semiconductor structures and other forms of SiO2 were highlighted.

The E′ Center and Oxygen Vacancies in SiO2. S.T.Pantelides, Z.Y.Lu, C.Nicklaw, T.Bakos, S.N.Rashkeev, D.M.Fleetwood, R.D.Schrimpf: Journal of Non-Crystalline Solids, 2008, 354[2-9], 217-23