A Novel Program Scheme to Optimize Program Disturbance in Dual-Deck 3D NAND Flash Memory

Abstract

The dual-deck architecture with aligned upper and lower decks is considered a promising technology to meet the demand of increasing word-line (WL) layers of 3D NAND flash. However, the relevant reliability studies are still lacking for the dual-deck 3D NAND array. In this work, it is reported an abnormal program disturbance phenomena of the bottom WLs in the upper-deck, and the physical mechanisms were studied. According to experimental analysis and TCAD simulations, the un-programmed dummy WLs at the joint region can introduce excessive joint residual electrons in the channel before the program, resulting in insufficient channel self-boosting potential, which is responsible for the degraded program disturbance. Thus, a novel program scheme is proposed to alleviate the program disturbance, which has been validated by experiments.