RDIS: Tolerating Many Stuck-At Faults in Resistive Memory

Abstract

With their potential for high scalability and density, resistive memories are foreseen as a promising technology that overcomes the physical limitations confronted by charge-based DRAM and flash memory. Yet, a main burden towards the successful adoption and commercialization of resistive memories is their low cell reliability caused by process variation and limited write endurance. Typically, faulty and worn-out cells are permanently stuck at either ‘0’ or ‘1’. To overcome the challenge, a robust error correction scheme that can recover from many hard faults is required. In this paper, we propose and evaluate RDIS , a novel scheme to efficiently tolerate memory stuck-at faults. RDIS allows for the correct retrieval of data by recursively determining and efficiently keeping track of the positions of the bits that are stuck at a value different from the ones that are written, and then, at read time, by inverting the values read from those positions. RDIS is characterized by a very low probability of failure that increases slowly with the relative increase in the number of faults. Moreover, RDIS tolerates many more faults than the best existing scheme—by up to 95 percent on average at the same overhead level.