Research Topics-V-NAND

Our laboratory conducts research on improving the reliability of 3D V-NAND flash memory, with a focus on enhancing retention characteristics and analyzing degradation mechanisms induced by program/erase (P/E) cycling. To improve retention in V-NAND flash memory, we investigate threshold voltage distribution shifts and charge loss behavior after program operation, and explore methods to enhance retention through optimization of P/E conditions and operation algorithms. In addition, we quantitatively analyze the physical degradation of the tunnel oxide, charge-trap layer, and channel interface caused by repeated P/E cycling, as well as the resulting degradation in P/E efficiency, retention characteristics, and read noise behavior. Through these studies, we aim to understand the reliability limitations of V-NAND and propose device/operation level optimization strategies to improve the lifetime and stability of high-density memory devices.