Impact of Program–Erase Operation Intervals at Different Temperatures on 3D Charge-Trapping Triple-Level-Cell NAND Flash Memory Reliability

Abstract

Three-dimensional charge-trapping (CT) NAND flash memory has attracted extensive attention owing to its unique merits, including huge storage capacities, large memory densities, and low bit cost. The reliability property is becoming an important factor for NAND flash memory with multi-level-cell (MLC) modes like triple-level-cell (TLC) or quad-level-cell (QLC), which is seriously affected by the intervals between program (P) and erase (E) operations during P/E cycles. In this work, the impacts of the intervals between P&E cycling under different temperatures and P/E cycles were systematically characterized. The results are further analyzed in terms of program disturb (PD), read disturb (RD), and data retention (DR). It was found that fail bit counts (FBCs) during the high temperature (HT) PD process are much smaller than those of the room temperature (RT) PD process. Moreover, upshift error and downshift error dominate the HT PD and RT PD processes, respectively. To improve the memory reliability of 3D CT TLC NAND, different intervals between P&E operations should be adopted considering the operating temperatures. These results could provide potential insights to optimize the lifetime of NAND flash-based memory systems.