High-Density NAND-Like Spin Transfer Torque Memory with Spin Orbit Torque Erase Operation

We present a NAND-like spintronics memory (NAND-SPIN) device for high-density non-volatile memory applications. Fast erasing and programming of magnetic tunnel junction (MTJ) are implemented with two unidirectional currents generating spin orbit torque (SOT) and spin transfer torque (STT), respectively. The asymmetric switching drawback of STT mechanism can be definitively overcome as only anti-parallel to parallel operation happens for NAND-SPIN programming, which allows lower switching current, smaller access transistor, and reduced maximum write voltage across the MTJ. By sharing the SOT-induced erase operation in a nanowire, the area overhead due to the three-terminal structure can be also eliminated. Simulation results show that NAND-SPIN can achieve 3 ∼ 5 × reduction in write energy compared to STT-MRAM, and 2 ∼ 4 × less bit-cell area than SOT-MRAM at 28 nm node.