A novel speed-up coding method in quadruple-level-cell 3D NAND flash memory

As more and more demand on high density storage, 3D NAND Flash memories have developed into multi-level cell and triple-level cell. With the charge-trapping technology adopted in 3D NAND Flash, it is possible to achieve quadruple-level-cell (QLC) which brings higher density capability. Meanwhile, the program coding method makes significant impact on the efficiency of the lockout operation in the program verification. A novel speed-up coding method is presented in this paper, which reduces nearly 30% time delay and 40% power consumption during the verify lockout operation in the QLC memory.