A fast WLR Test for the evaluation of EEPROM Endurance

In this paper a fast wafer level reliability (fWLR) test for the determination of EEPROM endurance is proposed. The accumulated degradation through dynamic stress performed on EEPROMs is related to bipolar static stress via stressing of simple capacitor test-structures. To evaluate EEPROM endurance, we extract oxide charge from EEPROM-arrays as well as from corresponding test- structures and correlate oxide charge build-up in both device types. Analytic formulas for the threshold voltage degradation are then used to model EEPROM endurance from data based on these test-structures. Endurance evaluation using this method is ten to fifteen times faster compared to evaluations based directly on EEROM devices.