Saturation of radiation-induced threshold-voltage shifts in thin-oxide MOSFETs at 80 K

Hole trapping in thin-oxide MOSFETs at 80 K is examined. The existing field-collapse model accurately predicts saturation of the hole trapping in a 26-nm oxide, but it overestimates the saturation by a factor of two in a 9.5-nm oxide. A revised model, which accounts for recombination of radiation-induced electrons with previously trapped holes, gives a much improved fit to the thin-oxide data at saturation. The conclusion is that recombination of drifting electrons with previously trapped holes is probably an important effect which contributes to threshold-voltage shift saturation at high total doses in thin oxides