Nonvolatile Multistates Memories for High-Density Data Storage

TLDR

The realization of energy‑efficient, high‑density, nonvolatile, fast, low‑cost memory devices remains a major challenge, and nonvolatile multistate memory (NMSM) offers a promising solution by storing multiple bits per cell, enhancing density without scaling, and enabling low‑power neuromorphic computing. The review surveys recent progress and challenges in device architectures, material innovations, and working mechanisms of various NMSMs, including flash, MRAM, RRAM, FeRAM, and PCM. The authors compare the properties and performance of these NMSMs, highlighting their potential for highly integrated memory hierarchies.

Abstract

In the current information age, the realization of memory devices with energy efficient design, high storage density, nonvolatility, fast access, and low cost is still a great challenge. As a promising technology to meet these stringent requirements, nonvolatile multistates memory (NMSM) has attracted lots of attention over the past years. Owing to the capability to store data in more than a single bit (0 or 1), the storage density is dramatically enhanced without scaling down the memory cell, making memory devices more efficient and less expensive. Multistates in a single cell also provide an unconventional in-memory computing platform beyond the Von Neumann architecture and enable neuromorphic computing with low power consumption. In this review, an in-depth perspective is presented on the recent progress and challenges on the device architectures, material innovation, working mechanisms of various types of NMSMs, including flash, magnetic random-access memory (MRAM), resistive random-access memory (RRAM), ferroelectric random-access memory (FeRAM), and phase-change memory (PCM). The intriguing properties and performance of these NMSMs, which are the key to realizing highly integrated memory hierarchy, are discussed and compared.