EFFECTS OF TEMPERATURE AND DEFECTS ON BREAKDOWN LIFETIME OF THIN SIO2 AT VERY-LOW VOLTAGES

This paper investigates the physics of voltage and temperature accelerated breakdown testing of silicon dioxide within the framework of an anode hole injection model which can predict low voltage (3.3 V and below) breakdown lifetime. The field acceleration rate is shown to be independent of temperature, while the reduction of oxide breakdown lifetime at increased temperature is due to the oxide's enhanced susceptibility to damage caused by the holes' transport through the oxide. This paper also investigates defect related breakdown, showing that defects can be mathematically modeled as effective thinning even for aggressively scaled oxides. The effective thickness statistic derived from ramp breakdown or high-field lifetime or charge-to-breakdown tests enables determination of the oxide integrity of a specific oxide technology. For 3.3 V operation, an oxide technology must provide an effective thickness of 44 angstrom; for 2.5 V operation, 34 angstrom.