High Perpendicular Anisotropy in Mo-Inserted Mg Composite Free Layer for Nonvolatile Magnetoresistive Random Access...

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Devices

Background:

• Nonvolatile memory (NVM) demand is increasing across various applications.
• Spin-transfer-torque magnetoresistive random access memory (STT-MRAM) is a scalable NVM solution, but faces challenges with temperature sensitivity affecting switching voltage (V_SW) and thermal stability (Δ).

Purpose of the Study:

• To introduce a universal temperature-friendly nonvolatile MRAM (UTF-NVMRAM) based on STT-MRAM technology.
• To minimize temperature sensitivity in V_SW and Δ for reliable operation between 4K and 400K.
• To ensure compatibility with back-end-of-line annealing processes.

Main Methods:

• Optimized the MgO/MgO_x capping layer.
• Incorporated Molybdenum (Mo) into a composite-free layer (CFL) with an Mg spacer.
• Utilized an STT-MRAM framework for device design.

Main Results:

• Achieved low V_SW sensitivity (V_SW/T ≈ 0.68 mV/K) and low Δ sensitivity (Δ/T ≈ 0.1/K).
• Demonstrated retention exceeding 10 years, write error rate below 1 ppm, operating speed of 10 ns, and endurance >10¹¹ cycles across the full temperature range.
• Maintained a large write margin without compromising magnetoresistance ratio or switching current.

Conclusions:

• UTF-NVMRAM exhibits minimal temperature sensitivity in key performance metrics.
• The developed NVMRAM is suitable for wide-temperature applications, offering a promising solution based on commercialized STT-MRAM.
• The design ensures high performance, reliability, and compatibility with manufacturing processes.