Reliable sub-nanosecond switching of a perpendicular SOT-MRAM cell without external magnetic field

摘要

The steady increase in performance and speed of modern integrated circuits is continuously supported by the ongoing miniaturization of complementary metal-oxide semiconductor (CMOS) devices. However, a rapid growth of the dynamic and stand-by power due to transistor leakages becomes a pressing issue. A promising way to stop this trend is to introduce non-volatility. The development of an electrically addressable nonvolatile memory combining high speed and high endurance is essential to achieve these goals. It is particularly promising to employ non-volatility in the main computer memory as a replacement of conventional volatile CMOS-based DRAM. To further reduce the energy consumption, it is essential to also replace the caches (SRAM) in modern hierarchical multilevel processor memory structures with a non-volatile memory technology. The spin-orbit torque magnetic random access memory (SOT-MRAM) combines non-volatility, high speed and high endurance and is thus suitable for applications in caches. However, its development is still impeded by the necessity of a static in-plane magnetic field. We propose a magnetic field-free perpendicular SOT-MRAM, based on a crossbar architecture and the use of two consecutive orthogonal sub-nanosecond current pulses. In this way small layout footprint and high integration density are guaranteed.