Fowler-Nordheim characteristics of electron irradiated MOS capacitors

MOS capacitors with 8 nn thick oxides have been irradiated by an 8 MeV LINA C electron beam. C-V and I-V measurements have shown a positive trapped cha rge, higher for irradiation performed under negative gate bias, as a conseq uence of preferential charge recombination at the cathodic interface. No sa turation of the positive trapped charge is measured up to 20 Mrad(Si). Neut ral defects induced by irradiation have been studied, by performing positiv e and negative Fowler-Nordheim injection. The distribution of neutral defec ts is similar to that of trapped holes, indicating a correlation between tr apped holes and neutral defects. Electrical stresses performed after irradi ation have shown that the accumulation kinetics of oxide defects is similar in both unirradiated and irradiated devices.