Separation of Lateral Migration Components by Hole During the Short-Term Retention Operation in 3-D NAND Flash Memories

Abstract

In this brief, we modeled the charge loss in the program verify level 1 (PV1) during the short-term retention operation. As a result, we confirmed that the charge loss in the lateral direction [lateral migration (LM)] was affected by the residual hole at the edge of the target word line (WL). Unlike the other PV levels, LM could be modeled separately in the PV1 by LM caused by electrons (LME) and LM caused by the residual hole (LMH). Also, PV1, which stores a relatively small amount of electrons compared to the other PV levels, was hardly affected by the adjacent cells, so there was almost no difference between solid (S/P) and checker-board (C/P). In order to model the PV1 state, we carried out the modeling considering the four charge loss mechanisms based on the short-term retention data measured at various temperatures (25–115 °C).