Dynamic partitioning to mitigate stuck-at faults in emerging memories

Abstract

Emerging non-volatile memories have many advantages over conventional memory. Unfortunately, many are susceptible to write endurance challenges, resulting in stuck-at faults. Existing mitigation methods statically partition and invert data within a block containing such faults (partition-and-flip) to ensure data is written to match stuck-at cells such that they may remain in service. Unfortunately, these schemes have limited fault tolerance capabilities and require the assumption that their auxiliary bits are fault free. We propose a dynamic partitioning scheme that improves the number of tolerated stuck-at faults and simultaneously protects auxiliary bits. Dynamic partitioning can significantly improve the fault tolerance over existing static partitioning approaches with an equal number of auxiliary bits. Moreover, it can often still improve fault tolerance while reducing the number of auxiliary bits. Compared to flip-N-write and Aegis, a leading mitigation scheme, dynamic partitioning can achieve 7–72% and 5–53 x lower write error rates, respectively, for the same capacity overhead with a stuck-at-fault rate of 10−3.