Impact of Mechanical Stress to Cell Characteristics in Vertically Stacked NAND Flash Structure

Abstract

The stress distribution and the impact of them to cell characteristics are investigated in vertically stacked NAND flash memory. It is revealed that the stress of contact hole depends on the distance from the tungsten common source line(CSL) slit, which changed the NAND cell characteristics more than 4% respectively. Therefore, position of channel hole contact affects the uniformity of the NAND cell taking into consideration the mechanical stress and should be considered in cell design.