A Comprehensive Modeling and Benchmarking Framework for Two-Terminal In-Plane Magnetic Anisotropy SOT-MRAM

In this study, a modeling and benchmarking framework is presented to assess compact two-terminal (2T) in-plane magnetic anisotropy spin-orbit torque magnetic random-access memory (IMA SOT-MRAM) cells. Although a previously proposed one-transistor one-magnetic tunnel junction configuration, with its 2T configuration, offers a more compact cell design that improves the cell density compared to a three-terminal (3T) design, it suffers from significant current crowding at the edge of the device and does not provide any notable advantage in terms of write time or energy. Here, we analyze a 2T variant incorporating a fixed layer with a length half of the free layer; this increases the effective path electrons pass through the SOT layer and provides a measurable benefit in terms of write energy and conduction current density. Two materials for the SOT channel—AuPt and β–W—are investigated. With the β–W SOT channel, the IMA 2T SOT-MRAM cell featuring a half-fixed layer achieves a 25% decrease in maximum conduction current density and a 16% decrease in write energy compared to the conventional 3T IMA SOT-MRAM. Also, the maximum conduction current densities for the IMA cases are significantly lower compared to those of the field-assisted perpendicular magnetic anisotropy case. These results indicate that the half-fixed 2T architecture—when paired with CMOS-compatible β–W —offers a practical path to denser, lower energy in-plane SOT-MRAMs.