Impacts of Lateral Charge Migration on Data Retention and Read Disturb in 3D Charge-trap NAND Flash Memory

Abstract

For deeper insights into the reliabilities of 3D charge-trap (CT) flash memory, we investigated the impacts of lateral charge migration (LCM) on data retention (DR) and read disturb (RD) by TCAD simulations. With discussions on the influence of neighbor cells' states and defect levels, it is found that LCM caused charge accumulation under the external electric fields could be the dominant reason to explain experimentally observed abnormal RD. Our results strongly suggest that appropriate read cycling could be an effective way to retrieve threshold voltage (Vth) down-shifts during data retention.