Breakdown characteristics of gate and tunnel oxides versus field and temperature

The wearout and breakdown parameters of representative gate and tunnel oxides are evaluated versus temperature, electric field and polarity. A frontier close to 127°C between two regions with different activation energies is clearly demonstrated. However, the negative charge build-up under high field stress is correlated with the breakdown. The field acceleration factor is found to be constant in the range 8·5–12·5 MV/cm. The time-to-breakdown distributions can be described both by the E and the 1/E models. Finally, the thickness dependence of the field acceleration factor is quantified for oxide layers with a thickness in the range between 10 nm and 50 nm.