HOT-CARRIER-INDUCED ELECTRON-MOBILITY AND SERIES RESISTANCE DEGRADATION IN LDD NMOSFETS

The mobility and the series resistant degradation of LDD NMOSFET's wer e determined independently for the first time. Three device structures with different styles of the drain engineering: 1) the modestly doped LDD; 2) large-angle-tilt implanted drain, and 3) the buried LDD were studied. We observed clearly that the series resistant drift dominates the initial device degradation and the relative importance of the mob ility degradation increases as the stress time proceeds. Our work prov ides a useful guideline for the device reliability optimization and fo r the development of the device degradation model for the circuits rel iability simulation.