Emerging Memory Technologies: Recent Trends and Prospects

TLDR

This tutorial introduces the fundamentals of emerging nonvolatile memory technologies such as STT‑MRAM, PCRAM, and RRAM. The tutorial reviews cell characteristics, array architectures (1T1R and cross‑point), design challenges (write‑current scaling and sneak‑path mitigation), and future applications including 3D integration, radiation hardness, and novel uses such as physical unclonable functions, FPGA routing switches, logic‑in‑memory, and neuromorphic devices. Recent progress includes megabit‑to‑gigabit prototype chip demonstrations.

Abstract

This tutorial introduces the basics of emerging nonvolatile memory (NVM) technologies including spin-transfer-torque magnetic random access memory (STTMRAM), phase-change random access memory (PCRAM), and resistive random access memory (RRAM). Emerging NVM cell characteristics are summarized, and device-level engineering trends are discussed. Emerging NVM array architectures are introduced, including the one-transistor-one-resistor (1T1R) array and the cross-point array with selectors. Design challenges such as scaling the write current and minimizing the sneak path current in cross-point array are analyzed. Recent progress on megabit-to gigabit-level prototype chip demonstrations is summarized. Finally, the prospective applications of emerging NVM are discussed, ranging from the last-level cache to the storage-class memory in the memory hierarchy. Topics of three-dimensional (3D) integration and radiation-hard NVM are discussed. Novel applications beyond the conventional memory applications are also surveyed, including physical unclonable function for hardware security, reconfigurable routing switch for field-programmable gate array (FPGA), logic-in-memory and nonvolatile cache/register/flip-flop for nonvolatile processor, and synaptic device for neuro-inspired computing.