Word-line batch Vth modulation of TLC NAND flash memories for both write-hot and cold data

Abstract

Word-line Batch Vth Modulation (WBVM) is proposed as a comprehensive solution for both write-hot and cold data to improve the reliability of Triple Level Cell (TLC) NAND Flash memories. For write-hot data, WBVM Vth score modulation decreases the program-disturb errors by 49% and enhances the endurance by 1.8-times of 2D-TLC NAND Flash. On the other hand, for write-cold data, WBVM BER score modulation decreases the data-retention errors by 36% and extends the acceptable data-retention time by 2.3-times of 2D-TLC NAND Flash. For 3D vertical TLC NAND Flash memory, the data-retention errors decrease by 13% and the acceptable data-retention time is extended by 1.4-times.