A testing technique to characterize E/sup 2/PROM's aging and endurance

The authors present a testing method for monitoring E/sup 2/PROM (electrically erasable programmable ROM) cell aging. The technique is not based on any particular assumption about cell technology: hence it can be used to characterize wearout dynamics in all cases in which charge trapped in tunnel oxide is the main failure mechanism. The method is validated by means of a wide set of measurements performed with automatic test equipment. The characterization can be directed to single cells, thus making it possible to study the main layout dependences of aging phenomena. Possible criticalities of the virgin devices (with respect to supply voltage temperature, etc.) can be determined. A procedure has been developed to extrapolate data obtained with a few programming cycles in order to obtain first-order estimates of the actual device endurance.<
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