Automatic Data Repair Overwrite Pulse for 3D-TLC NAND Flash Memories with 38x Data-Retention Lifetime Extension

This paper proposes Automatic Data Repair Overwrite Pulse (ADROP) to improve the reliability of 3D-TLC NAND flash. When ECC cannot correct errors, ADROP overwrites data including errors to failed memory cells and thus adaptively injects electrons to memory cells that were lost during the data-retention by the lateral charge migration and the vertical charge de-trap. As a result, the data-retention lifetime increases by 38.3-times. ADROP is composed of VTH Shift Recovery Pulse (VSRP) and Data Repair Pulse (DRP) that are implemented in the SSD controller without circuit area overhead.