Understanding the Latent Impact of Residual Particles in 3D NAND

Abstract 3D NAND memory, featuring vertically stacked memory cells to enhance storage density and performance, serves as a critical component in modern data storage solutions and AI applications. In this paper, we investigated the electrical impact of memory hole (MH) mis-formation defects in a multi-tier three dimensional (3D) NAND memory technology. Despite being confined to local word lines (WLs) and source lines (SLs), such defects cause a global impact to all the memory cells in the same plane by slowing down their program speed. Specifically, the bit line potential of victim cells is disturbed when quick pass write (QPW) program technique is implemented. Such disturb originates from the interaction between source line and global bit line through the aggressor memory cells. Based on the failure mechanism, several approaches were proposed to improve the screen efficiency for these defects, which could otherwise become latent system failures.