Breakdown measurements of ultra-thin SiO/sub 2/ at low voltage

MOSFETs with oxide thickness from t/sub ox/=1.4 to 2.2nm have been stressed for times exceeding one year, at voltages in the range V/sub g/=1.9-4V. The data are compared with previous model calculations. The voltage acceleration of the charge-to-breakdown (Q/sub BD/) is explained in terms of a weak yet statistically significant voltage dependence of the critical defect density at breakdown (N/sup BD/), and a stronger than expected voltage dependence of the defect generation probability (P/sub g/) for the thinnest oxides studied.