Post-cycling data retention failure in multilevel nor flash memory with nitrided tunnel-oxide

Post-cycling data retention characteristics of a multilevel NOR flash memory with nitrided tunnel-oxide is presented. Results show that retention behavior is strongly related to the amount of interface trap generation rather than that of oxide trap, indicating detrapping from near interface trap is a major factor for threshold voltage shift. Process conditions including nitrogen concentration at the interface and subsequent annealing of nitrided tunnel-oxide by O
₂
are found to be related to the generation of interface trap and resultant postcycling retention.