Endurance-based Dynamic VTHDistribution Shaping of 3D-TLC NAND Flash Memories to Suppress Both Lateral Charge Migration and Vertical Charge De-trap and Increase Data-retention Time by 2.7x

Shun Suzuki, Yoshiaki Deguchi, Toshiki Nakamura, Ken Takeuchi

Abstract: Lateral charge migration and vertical charge detrap degrade the reliability of 3D-Triple-Level Cell (TLC) NAND flash. Lateral charge migration is dominant at the low write/erase (W/E) endurance and vertical charge de-trap is dominant at the high endurance. Conventional techniques address only one of these problems. This paper proposes Endurance-based Dynamic V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> Distribution Shaping (DVDS) to suppress both errors at a wide range of the endurance. At low (1) and high (2k) endurance, measured errors decrease by 27% and 20% and measured acceptable data-retention time increases by 1.7x and 2.7x, respectively.