Improving cell current in 3D NAND flash memory with fixed oxide charge

This paper addresses the challenge of declining cell current in 3D NAND Flash memory. We propose a novel approach to deposit a positive fixed oxide charge on the backside adjacent to the filler oxide after forming a poly-Si channel, effectively improving the cell current flow within the entire string. Through TCAD simulations and experimental device fabrication, we demonstrate a significant enhancement in cell current by approximately 30%. Furthermore, we analyze the impact of positive fixed charge on channel current and investigate the influence of Poly-Si channel thickness and liner oxide thickness on current improvement. Our findings indicate promising avenues for improving 3D NAND Flash memory technology, contributing to its continued advancement in the future.