Correlation between preirradiation 1/f noise and postirradiation oxide-trapped charge in MOS transistors

The authors have performed a detailed comparison of the preirradiation 1/f noise and the radiation-induced threshold voltage shifts due to oxide-trapped and interface-trapped charge, ΔV_ot and ΔV_it, for enhancement-mode, 3-μm-gate, n-channel MOS transistors taken from seven different wafers processed in the same lot. These wafers were prepared with gate oxides of widely varying radiation hardness. It is shown that the preirradiation 1/f noise levels of these devices correlate strongly with the postirradiation ΔV_ot , but not with the postirradiation ΔV_it. These results suggest that 1/f noise measurements may prove useful in characterizing and predicting the radiation response of MOS devices