A Multilayer Approach to Designing Energy-Efficient and Reliable ReRAM Cross-Point Array System

In this paper, we study the 1-selector-1-resistor (1S1R) cross-point resistive random access memory (ReRAM) array because of its high density, fast access time, and ultralow stand-by power. Specifically, we focus on an access scheme where a data line is parallelly accessed from multiple subarrays with multibits accessed per subarray. A direct implementation of such a scheme has high energy efficiency but lower reliability compared with a single bit per subarray baseline scheme. So this paper proposes a low cost multilayer approach to improve energy-efficiency of multibits per access scheme without compromising reliability. At the cell level, we show how proper choices of bit-line and source-line voltage and SET recovery help reduce error rate by ten times. At the system level, we propose a new rotated multiarray access scheme where the average error rate of every accessed data line is one order of magnitude lower than the worst case, making it possible to achieve block failure rate of 10^-10 with a simple Bose, Chaudhuri, and Hocquenghem t = 4 code. We show that for a 1 GB 1S1R ReRAM, the proposed approach can reduce energy by 41% with 2% extra area while maintaining latency and reliability compared with the baseline system.