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

In recent years, demand for nonvolatile memory (NVM) has surged across diverse applications. Spin-transfer-torque magnetoresistive random access memory (STT-MRAM) is a leading scalable solution for embedded NVM, mass-producible below 28 nm, offering superior performance over other NVM technologies. However, achieving low switching voltage (V_SW) and high thermal stability (Δ) across temperatures from 4 to 400K remains challenging due to MRAM's temperature sensitivity. This study introduces a universal temperature-friendly nonvolatile MRAM (UTF-NVMRAM) based on an STT-MRAM framework, designed for applications spanning 4 to 400K. By optimizing the MgO/MgO_x capping layer and incorporating Mo into a CoFeB composite-free layer (CFL) with an Mg spacer, this design minimizes temperature sensitivity in V_SW and Δ while ensuring potential compatibility with back-end-of-line annealing temperatures. It maintains a large write margin without compromising the magnetoresistance ratio or switching current. The device achieves low V_SW sensitivity (V_SW/T ≈ 0.68 mV/K), low Δ sensitivity (Δ/T ≈ 0.1/K) with retention exceeding 10 years, a write error rate below 1 ppm, an operating speed of 10 ns, and endurance surpassing 10¹¹ cycles across the full temperature range. These attributes position UTF-NVMRAM as the most promising NVM solution based on commercialized STT-MRAM technology for wide-temperature applications.