An endurance evaluation method for flash EEPROM

Trap generation is hard to estimate in a Flash cell due to a dynamic stress field during program and erase. In this paper, a linear correlation is found between the erase state V/sub T/ rollup and cycling V/sub T/ window. With the knowledge of the time dependence of erase stress field based on Fowler-Nordheim (FN) tunneling, the V/sub T/ rollup during cycling is evaluated by incorporating field dependent oxide trap generation. The extracted /spl Delta/V/sub T/ degradation slope during constant FN stress can be applied quantitatively to predict the V/sub T/ window closure during Flash cell cycling.