Cross-Temperature Reliability of 3D NAND: Cell-to-Cell Variability Analysis and Countermeasure

Cross-temperature effect is a significant reliability concern for 3D NAND Flash memory. In this paper we explore the origin of cross-temperature reliability by measuring the cell threshold voltage (V
th
) distribution at different temperatures. We observe significant cell-to-cell variability in the temperature coefficients causing distribution widening. We provide a conceptual picture to understand the distribution widening based on sub-threshold slope factor variation. We also discuss two system level countermeasures to minimize the cross-temperature effects.