Experimental evidence of two species of radiation induced trapped positive charge

The effects of alternating bias anneals of MOS transistors following either X-irradiation or Fowler-Nordheim tunneling have been studied. It is found that some of the generated defects can be repeatedly charged and discharged with a change of applied oxide field. Two models that may explain this phenomenon are discussed. One assumes a single defect, the E' center, while the other is a two-defect model. The authors present results that are shown to be more consistent with the two-defect model.< >