13.3 A 280-Layer 1Tb 4b/cell 3D-NAND Flash Memory with a 28.5Gb/mm2 Areal Density and a 3.2GB/s High-Speed IO Rate

Abstract

3D-NAND Flash memory is evaluated as a key device that is handling the explosive data growth, showing steady bit growth and areal density increases >30% every year. In particular, the 4b/cell (QLC) 3D-NAND technology is appearing to be one of the most promising solutions to meet the market demand with excellent cost effectiveness, while QLC technology is being gradually adopted by various storage applications [1]. However, there are several challenges that need addressing so that QLC technology is adopted rapidly by the market: (1) is the reprogram with on-chip buffered program (OBP) [2], and (2) the low performance caused by the 16-state verify.