All-Electrical Control of Compact SOT-MRAM: Toward Highly Efficient and Reliable Non-Volatile In-Memory Computing

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) van der Waals (vdW) ferromagnets offer scalability and controllable ferromagnetism for non-volatile in-memory computing (nv-IMC).
• Addressing the memory wall bottleneck requires innovative computing architectures and materials.
• Emerging 2D materials like Fe3GeTe2 present unique properties for spintronic applications.

Purpose of the Study:

• To develop a new non-volatile spin-orbit torque (SOT) magnetic tunnel junction (MTJ) device utilizing 2D Fe3GeTe2.
• To demonstrate high-speed, field-free magnetization switching in the Fe3GeTe2-based MTJ.
• To explore the potential of this device for energy-efficient nv-IMC and Boolean logic operations.

Main Methods:

• Fabrication of a Fe3GeTe2/MgO/Fe3GeTe2 heterostructure for SOT-MTJ devices.
• Investigation of room-temperature ferromagnetism and spin-dependent transport properties of 2D Fe3GeTe2.
• Device characterization focusing on magnetization switching dynamics and sensing margins.
• Circuit-level simulations to evaluate performance in a 3-transistor-2-MTJ (3T2M) cell and crossbar array architecture.

Main Results:

• Achieved uni-polar and high-speed field-free magnetization switching by tuning torque coefficients in the Fe3GeTe2 free layer.
• Demonstrated a 3T2M cell with complementary data storage and significantly enhanced sensing margins (201.4% for '1', 276% for '0').
• Executed Boolean logic operations (AND/NAND, OR/NOR) in a 3T2M crossbar array with 24 ps latency and 2.47 fJ/bit power consumption.
• Outperformed traditional CoFeB-based MTJ memory cells in terms of speed and power efficiency.

Conclusions:

• The developed 2D Fe3GeTe2-based SOT-MTJ device shows great promise for high-performance, compact SOT magnetic random-access memory.
• This technology facilitates highly reliable and energy-efficient nv-IMC applications.
• The findings pave the way for next-generation spintronic computing devices leveraging 2D materials.