On the potential of correlated materials in the design of spin-based cross-point memories (Invited)

Cross-point architectures are promising for designing dense memory arrays. However, sneak current paths in a cross-point array necessitates the use of non-linear selectors. In this paper, we analyze the potential of employing correlated materials exhibiting abrupt insulator-metal transitions as selectors to design cross-point memories based on magnetic tunnel junctions (MTJs). We analyze the properties of the correlated materials and co-design MTJs and the selector to optimize the energy efficiency and robustness of the memory array. Our analysis points to the need of a correlated material with a large ratio of insulator and metal resistivities along with appropriate critical currents for the phase transitions (the values of which depend on the absolute value of the resistivities). We discuss that the design constraints lead to a restriction on the range of the selector length, which is closely related to the oxide thickness of the MTJ. Comparison of the cross-point architecture with standard architecture shows the benefits in the former in terms of 7% larger sense margin and 5X higher integration density at iso-read stability. However, this comes at the cost of 2X lower write speed (due to two-cycle write) and 11%-19% increase in the read/write power (due to sneak current in the cross-point array).