Polarity dependence of dielectric breakdown in scaled SiO/sub 2/

We have investigated polarity dependence of dielectric breakdown under constant current stress in scaled SiO/sub 2/ dielectrics. Results show that high-field-induced interface state generation is reduced as oxide thickness scales down and charge-to-breakdown (Q/sub BD/) for positive gate bias (+V/sub g/) increases with decreasing oxide thickness. However, Q/sub BD/ for negative gate bias (-V/sub g/) shows an opposite trend to Q/sub BD/(+V/sub g/), i.e. Q/sub BD/(-V/sub g/) decreases dramatically with decreasing oxide thickness. Therefore, there is an increased polarity dependence of dielectric breakdown when oxide thickness scales down. A physical model based on the degradation of structural transition layer (STL) and interface is proposed to explain the observed trends in Q/sub BD/.<>