Compact Modeling of Differential Spin-Orbit Torque based MRAM

Abstract

Magnetic tunnel junction (MTJ) is the basic storage component of magnetic random access memory (MRAM). In recent years, many structures such as in-plane MTJ, perpendicular magnetic anisotropy MTJ (pMTJ), spin transfer torque MTJ (STT-MTJ), spin-orbit torque MTJ (SOTMTJ), and complementary MTJ (cMTJ) are reported. Different structures and behavior are subject to the choice of anisotropy, switching mechanism and/or geometry of MTJ. This paper presents a compact modeling of differential spin-orbit torque (DSOT) based MRAM. Two structures serial DSOT and parallel DSOT are presented. Compact modeling using VerilogA is presented and device performance is reported. The results show an improvement in write energy and delay by 50% and 3.2 times respectively as compared to the single ended SOT device. In addition, it illustrates that serial DSOT structure is more energy efficient than parallel DSOT. The SPICE-based DSOT model can be useful for many high-performance hybrid spintronics/CMOS applications.