AC/DC CHARACTERIZATION OF NMOS AND PMOS HOT-CARRIER-INDUCED DEGRADATION UNDER AC/DC STRESS

The ac/dc measurement of NMOS and PMOS/Ja, shifts are compared following dc stress. The results of the/Jsal shifts are found to be the same. The ac/rfsat measurements were performed under a variety of different conditions (varying frequency, amplitude, and base level) and showed that hot-carrier-induced interfaced states are shallow and fast (<20 ns). AC versus dc stressing is also examined. In PMOS devices, pulsed drain stress is found to be generally quasi-static, while pulsed gate stress produced enhanced device degradation under certain bias conditions. In NMOS transistors ac drain stress was found to be quasi-static in strong device saturation, while ac gate stress resulted in significantly enhanced degradation. In weak device saturation, both gate and drain pulsing resulted in early catastrophic device failure. © 1990 IEEE