Spin-Transfer Torque Magnetoresistive Random Access Memory Technology Status and Future Directions

Spin-Transfer Torque Magnetoresistive Random Access Memory (STT-MRAM) is a non-volatile memory technology with a unique combination of speed, endurance, density, and ease of fabrication, which has enabled it to recently replace embedded Flash as the embedded non-volatile memory of choice for advanced applications, including automotive micro-controller units. In this review article, we describe the working principles of STT-MRAM, and provide a brief history of its development. We then discuss the requirements, product status, and outlook for four key STT-MRAM applications: standalone, embedded non-volatile memory, non-volatile working memory, and last-level cache. Finally, we review potential future directions beyond STT-MRAM, including spin-orbit torque MRAM (SOT-MRAM) and voltage control of magnetic anisotropy MRAM (VCMA-MRAM), with an emphasis on their technological potential.