30.2 A 1Tb 4b/Cell 144-Tier Floating-Gate 3D-NAND Flash Memory with 40MB/s Program Throughput and 13.8Gb/mm2 Bit Density

Continued improvement in the 3D NAND bit density is essential to satisfy the exponentially growing demand for data storage. The transition from 3b/cell (TLC) to 4b/cell (QLC) is a significant step towards delivering higher bit density. The increased program/erase (P/E) window, in 3D NAND technology, combined with improved program algorithms to alleviate interference from neighboring WL cells, has led to the successful deployment of two generations of QLC floating gate (FG) 3D NAND technology [1]. Further improvement in bit density, as well as the read and write performance will accelerate the adoption rate of QLC NAND into data-storage systems.