QLC Programmable 3D Ferroelectric NAND Flash Memory by Memory Window Expansion using Cell Stack Engineering

Abstract

3D ferroelectric NAND (Fe-NAND) Quad-level cell (QLC) operation has been demonstrated for the first time to our knowledge, using the 3D CTN NAND test vehicle for mass production. The 3D Fe-NAND is optimized by engineering the cell stack layers, enlarging a program/erase (PE) window up to 10.5 V. QLC operation is successfully verified with the minimum gap margin of 0.24 V. Endurance and data retention characteristics are also reported.