Influence of Channel Hole Remaining Ratio on Hemi-Cylindrical Vertical NAND Flash Memory

The influence of the channel hole remaining ratio (
CHRR
) on the hemi-cylindrical (HC) vertical NAND (VNAND) flash memory was investigated using both simulation and experimental data. Although HC VNAND flash memory is advantageous for increasing lateral memory density, it suffers from nonuniform carrier injection and low program/erase efficiency. In this study, the underlying physics of these disadvantages are discussed in terms of the proposed parameter,
CHRR
. Finally, based on the analysis, a recessed channel HC VNAND flash memory cell is proposed.