MLC nand flash retention error recovery scheme through word line program disturbance

Abstract

Aggressive scaling down of Nand Flash induced serious reliability degeneration. Endurance and data retention lifetime deteriorated has become important scaling barrier. In this paper we propose a data retention reliability enhancing scheme through word line program disturbance (RE-WPD) for high scaled Nand Flash. The key ideal of RE-WPD is injecting extra electrons into floating gate through word line program disturbance, and recovers data retention errors due to floating gate charge leakage. As the result, 54% data retention bit error rate and 67% endurance improvement is achieved on commercial 2Xnm MLC Nand Flash.