Voltage-Gate Assisted Spin-Orbit Torque Magnetic Random Access Memory for High-Density and Low-Power Embedded Application

Abstract

Voltage-gate assisted spin-orbit torque (VGSOT) writing scheme combines the advantages from voltage control of magnetic anisotropy (VCMA) and spin-orbit torque (SOT) effects, enabling multiple benefits for magnetic random access memory (MRAM) applications. In this work, we give a complete description of VGSOT writing properties on perpendicular magnetic tunnel junction (pMTJ) devices, and we propose a detailed methodology for its electrical characterization. The impact of gate assistance on the SOT switching characteristics are investigated using electrical pulses down to 400ps. The VCMA coefficient (ξ) extracted from current switching scheme is found to be the same as that from the magnetic field switch method, which is in the order of 15fJ/Vm for the 80nm to 150nm devices. Moreover, as expected from the pure electronic VCMA effect, ξ is revealed to be independent of the writing speed and gate length. We observe that SOT switching current characteristics are modified linearly with gate voltage (V_g), similar as for the magnetic properties. We interpret this linear behavior as the direct modification of perpendicular magnetic anisotropy (PMA) and nucleation energy induced by VCMA. At V_g = 1V, the SOT write current is decreased by 25%, corresponding to a 45% reduction in total energy down to 30fJ/bit at 400ps speed for the 80nm devices used in this study. Further, the device-scaling criteria are proposed, and we reveal that VGSOT scheme is of great interest as it can mitigate the complex material requirements of achieving high SOT and VCMA parameters for scaled MTJs. Finally, how that VGSOT-MRAM can enable high-density arrays close to two terminal geometries, with high-speed performance and low-power operation, showing great potential for embedded memories as well as in-memory computing applications at advanced technology nodes.

References in corpus (6)

• Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems
• Spin Transfer Torque Generated by the Topological Insulator Bi_2Se_3
• Ultrafast magnetization switching by spin-orbit torques
• Threshold current for switching of a perpendicular magnetic layer induced by spin Hall effect
• Single-shot dynamics of spin-orbit torque and spin transfer torque switching in three-terminal magnetic tunnel junctions
• Field-free switching of magnetic tunnel junctions driven by spin-orbit torques at sub-ns timescales

Cited by in corpus (10)

• Spin-orbit torque switching of magnetic tunnel junctions for memory application
• Interplay of voltage control of magnetic anisotropy, spin transfer torque, and heat in the spin-orbit torque switching in three-terminal magnetic tunnel junctions
• Field-Free Spin-Orbit Torque driven Switching of Perpendicular Magnetic Tunnel Junction through Bending Current
• Fabrication of voltage gated spin Hall nano-oscillators
• Tailoring the switching efficiency of magnetic tunnel junctions by the fieldlike spin-orbit torque
• Substrate-induced spin-torque-like signal in spin-torque ferromagnetic resonance measurement
• Pulse Shaping Strategies for Efficient Switching of Magnetic Tunnel Junctions by Spin-Orbit Torque
• Real-time dynamics of VCMA-assisted switching of magnetic tunnel junctions
• Impact of gate voltage on switching field of perpendicular magnetic tunnel junctions with a synthetic antiferromagnetic free layer
• Orbital Hybridization Induces Giant Cubic Rashba Effect at Cu/WO${}_3$ Interface