The ability to consistently reverse the magnetic alignment in materials, called magnetization switching, is crucial for the operation of most memory devices. One common method to achieve this involves generating a rotational force (torque) on electron spins using an electric current, a phenomenon known as spin-orbit torque (SOT).
Information storage devices utilizing this effect are known as spin-orbit torque magnetic random-access memories (SOT-MRAMs). These systems offer key benefits: data retention without power, faster switching speeds, and low energy consumption.
SOT-MRAM Breakthrough with Tungsten for Next-Gen Computing
A team from National Yang Ming Chiao Tung University, TSMC, the Industrial Technology Research Institute, and others recently developed a new SOT-MRAM using tungsten-based composite materials with strong spin-orbit coupling. Their memory device, outlined in a Nature Electronics paper, can be produced using existing semiconductor processes for large-scale manufacturing.
“Our motivation stemmed from the need for ultra-low power, high-speed, and dependable memory to support next-gen computing,” said Yen-Lin Huang, the paper’s first author, in an interview with Tech Xplore. “Although spin-orbit torque MRAM had been suggested for some time, the challenge was to achieve nanosecond switching, long retention, and large-scale integration using processes compatible with the semiconductor industry.”
Developing Speed and Durability: MRAM with Industry-Compatible Manufacturing
The primary goal of the recent study by Huang and his team was to create an MRAM that offers both speed and durability, while also being compatible with manufacturing processes commonly used in the electronics industry. The memory device they developed stores data in the magnetization direction of a thin ferromagnetic layer.
“Instead of a magnetic field, we use spin-orbit torque— a current through a tungsten layer flips the magnetization in about 1 ns,” Huang explained.
“Our MRAM combines Flash’s non-volatility with DRAM’s nanosecond speed, but uses less power and requires no refresh cycles. The key innovation here is stabilizing the tungsten phase to achieve both high spin efficiency and compatibility with industry-standard integration.”
1ns Switching & 10+ Years Retention in Scalable SOT-MRAM Prototype
The researchers developed a prototype with a 64-kilobit (kb) array and tested its performance under conditions similar to real-world use. The SOT-MRAM demonstrated an impressive switching speed of 1ns and a retention time exceeding 10 years.
“We stabilized a tungsten phase crucial for spin efficiency up to 700°C,” Huang explained. “Our study shows SOT-MRAM can scale for on-chip cache and embedded memory, driving energy-efficient AI and edge computing with speed and non-volatility.”
Advancing Scalable SOT-MRAM: Efficiency and Integration for Future Systems
Huang and his team’s work could open new opportunities for scalable, large-scale production of high-performance SOT-MRAMs using β-phase tungsten. Future research could build on this to develop faster, more stable memory systems that are compatible with current manufacturing processes.
“We’re now working on scaling up to megabit arrays and further reducing write currents to sub-picojoule/bit levels,” added Huang. On the physics side, we’re exploring new oxide and 2D interfaces to enhance efficiency and reliability. Another focus is system demos showing how MRAM can reduce power consumption in AI accelerators and mobile devices.
Read the original article on: Tech Xplore
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