W-Si SOT Magnetic Tunnel Junction for Low-Resistance Switching
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Solution Overview
Problem
Current spin-orbit torque (SOT)-based magnetic tunnel junctions face challenges in achieving high spin-orbit torque efficiency at low specific resistance and maintaining perpendicular magnetic anisotropy across various thermal treatment temperatures.
Innovation Solution
A spin-orbit torque-based magnetic tunnel junction incorporating a W—X alloy thin film, where W is tungsten and X includes group IV semiconductors and group III-V semiconductors, with a tungsten-silicon alloy as the spin-orbit active layer, allowing for spin-orbit torque switching and high efficiency, and a method of fabricating this junction by forming the W—X alloy on a substrate and thermally treating it to control switching current and maintain perpendicular magnetic anisotropy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional spin-orbit active layer is used, then the device structure is simple, but the spin-orbit torque efficiency is low and specific resistance is high
Solution Approach 1:
The patent uses a W—X alloy composite material where tungsten (W) provides high spin-orbit coupling and group IV or group III-V semiconductors (X) provide low specific resistance. This composite structure achieves both high spin-orbit torque efficiency and low specific resistance simultaneously, resolving the technical contradiction between these two parameters.
Solution Approach 2:
The patent changes the compositional parameters of the spin-orbit active layer by forming a W—X alloy with specific composition ratios. By adjusting the concentration of tungsten and semiconductor elements, the patent optimizes both the spin Hall angle (for torque efficiency) and the electrical resistivity, transforming the material properties to resolve the contradiction.
2Ease of operation
If thermal treatment temperature is increased to control switching current, then switching current decreases, but perpendicular magnetic anisotropy may be lost
Solution Approach 1:
The W—X alloy composite structure maintains perpendicular magnetic anisotropy stability at elevated thermal treatment temperatures (300-500°C) while still achieving reduced switching current. The synergistic combination of tungsten and semiconductor elements provides both the desired magnetic properties and electrical characteristics that resolve this contradiction.
Solution Approach 2:
The patent performs thermal treatment at optimized temperature ranges (300-500°C) to adjust the compositional and structural parameters of the W—X alloy. This thermal processing modifies the material properties to achieve lower switching current while preserving perpendicular magnetic anisotropy, resolving the contradiction between operational ease and compositional stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables high spin-orbit torque efficiency at low specific resistance and maintains perpendicular magnetic anisotropy across different thermal treatment temperatures, reducing switching current and enhancing magnetic properties.
Implementation Method 1
the spin-orbit torque (SOT) phenomenon that induces switching of a free layer using the spin Hall effect or the Rashba effect occurring when current flows in a parallel direction in a plane of a spin-orbit active layer adjacent to a free layer
Implementation Method 2
the spin-orbit torque (SOT) phenomenon that induces switching of a free layer using the spin Hall effect or the Rashba effect occurring when current flows in a parallel direction in a plane of a spin-orbit active layer adjacent to a free layer
Implementation Method 3
the value of tunneling current passing through a tunnel barrier is changed depending upon the state in which the spin direction of the adjacent free layer and pinned layer are arranged in parallel or antiparallel with the tunnel barrier interposed therebetween
Implementation Method 4
a magnetic tunnel junction must have perpendicular magnetic anisotropy (PMA). PMA means that the magnetization direction of a magnetic layer is perpendicular to a magnetic layer plane
Data Source
AI summary
Disclosed are a spin-orbit torque (SOT)-based magnetic tunnel junction and a method of fabricating the same. More particularly, the SOT-based magnetic tunnel junction includes a spin-orbit torque (SOT)-based magnetic tunnel junction, including: a spin-orbit active layer formed on the substrate; a free layer formed on the spin-orbit active layer; a tunnel barrier layer formed on the free layer; and a pinned layer formed on the tunnel barrier layer, wherein the spin-orbit active layer includes a W—X alloy (where W is tungsten and X includes at least one of group IV semiconductors and group III-V semiconductors).