Spin-Current Magnetic Memory Element With Perpendicular Anisotropy
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Solution Overview
Problem
Conventional spin-current switchable magnetic memory elements require high switching currents and low impedance, making them unsuitable for integration with CMOS technology, and they often necessitate sophisticated thin film synthesis techniques like molecular beam epitaxy for fabrication.
Innovation Solution
A spin-current switchable magnetic memory element is developed using a plurality of magnetic layers with perpendicular magnetic anisotropy, including alloys of rare-earth metals and transition metals, formed through a sputter deposition process, which allows for reduced switching currents and increased impedance without requiring advanced thin film synthesis technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional spin-current switchable magnetic memory elements are used, then magnetic memory functionality is achieved, but switching current is too large (mid 10^6 A/cm2) and impedance is too low (1-2 Ω-μm2) for CMOS integration
Solution Approach 1:
The patent changes the magnetic anisotropy parameter from in-plane to perpendicular magnetic anisotropy by using specific material combinations (CoFeB/MgO interfaces, Pt/Co interfaces). This parameter change enables lower switching current densities (around 10^5 A/cm2 or lower) while achieving higher impedance values (10-100 Ω-μm2 or higher), making the device compatible with CMOS integration requirements
Solution Approach 2:
The patent employs composite material structures including CoFeB/MgO tunnel junctions with Pt capping layers, and CoFeB/CoFeB spin-valve structures with Ru spacer layers. These composite materials provide both the necessary perpendicular magnetic anisotropy for low-current switching and the high impedance required for CMOS compatibility
2Manufacturing precision
If sophisticated thin film synthesis technology such as molecular beam epitaxy is used, then precise magnetic layer fabrication is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent identifies material parameter ranges that enable perpendicular magnetic anisotropy to be achieved through conventional sputter deposition rather than requiring molecular beam epitaxy. By optimizing layer thicknesses (e.g., CoFeB layers 3-10 nm, MgO barriers 1-3 nm) and using specific material compositions, the patent achieves the necessary precision with more accessible fabrication technology
Solution Approach 2:
The patent replaces expensive, complex molecular beam epitaxy equipment and processes with more widely available, cost-effective sputter deposition systems. This substitution maintains sufficient manufacturing precision for magnetic memory applications while dramatically reducing fabrication complexity and equipment requirements
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 the fabrication of magnetic memory elements with lower switching current densities and higher impedance, facilitating integration with CMOS technology and simplifying the manufacturing process by eliminating the need for sophisticated thin film synthesis methods.
Implementation Method 1
formed through a sputter deposition process
Implementation Method 2
The current-induced magnetic moment switching is achieved through the spin transfer torque
Implementation Method 3
a plurality of magnetic layers having a perpendicular magnetic anisotropy component
Data Source
AI summary
A spin-current switchable magnetic memory element (and method of fabricating the memory element) includes a plurality of magnetic layers having a perpendicular magnetic anisotropy component, at least one of the plurality of magnetic layers including an alloy of a rare-earth metal and a transition metal, and at least one barrier layer formed adjacent to at least one of the plurality of magnetic layers.