MRAM Magnetoresistance Element With Multilayer Pinned Layer Anisotropy
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Solution Overview
Problem
The crystal orientation of ferromagnetic layers in magnetoresistance effect elements is not adequately addressed, limiting the enhancement of perpendicular magnetic anisotropy, which is crucial for improving the magnetoresistance effect and reducing errors in magnetoresistive random access memory (MRAM) applications.
Innovation Solution
A magnetoresistance effect element is designed with a magnetization pinned layer comprising a first and second magnetic body sandwiched by a non-magnetic metal layer, where at least one of these magnetic bodies is configured with a multilayer structure of different materials alternately laminated directly above a non-magnetic layer, enhancing crystal orientation and magnetic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ferromagnetic layer is used with conventional structure, then the device complexity is low, but the perpendicular magnetic anisotropy is insufficient
Solution Approach 1:
The patent employs composite magnetic layer structures combining CoFeB (cobalt ferrite boride) and Pt (platinum) in alternating layers. This composite structure leverages the high magnetic anisotropy of CoFeB and the spin-orbit coupling properties of Pt to generate enhanced perpendicular magnetic anisotropy through spin-orbit coupling at the interfaces, thereby improving reliability without excessive complexity
Solution Approach 2:
The patent transitions from in-plane magnetization to perpendicular magnetization by introducing magnetic anisotropy in the vertical dimension. The multilayer structure with alternating magnetic and non-magnetic layers creates interfacial perpendicular magnetic anisotropy, effectively utilizing the vertical dimension to achieve the desired magnetic properties
2Reliability
If the crystal orientation of ferromagnetic layer is low, then the manufacturing process is simple, but the perpendicular magnetic anisotropy cannot be enhanced
Solution Approach 1:
The patent systematically varies critical parameters including the thickness of CoFeB and Pt layers, the number of repeating units, and deposition conditions to optimize crystal orientation. By controlling these parameters, the patent achieves high (001) orientation of CoFeB and (111) orientation of Pt, which are essential for generating strong perpendicular magnetic anisotropy
3Reliability
If a multilayer structure with alternating materials is used, then the magnetoresistance change rate is enhanced, but the device complexity increases
Solution Approach 1:
The patent divides the magnetization pinned layer into multiple discrete magnetic bodies (first magnetic body and second magnetic body) separated by non-magnetic metal layers. Each magnetic body can be independently optimized and controlled, allowing for enhanced magnetoresistance change rate through improved magnetic coupling while managing complexity through modular design
Solution Approach 2:
The patent introduces non-magnetic metal layers (such as Ru, Rh, Ir) as intermediaries between magnetic layers. These intermediary layers facilitate controlled magnetic coupling, enable independent magnetization control of adjacent magnetic bodies, and enhance the overall magnetoresistance effect without creating direct magnetic interactions that would increase complexity
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
This configuration improves the magnetic coupling force, reduces error rates in MRAM, and enhances the magnetoresistance change rate by optimizing the crystal orientation and perpendicular magnetic anisotropy of the ferromagnetic layers.
Implementation Method 1
a magnetoresistance effect element in which an insulating thin film is sandwiched between a pair of ferromagnetic layers. In the magnetoresistance effect element, a magnitude of a tunnel resistance changes depending on relative magnetization directions of the pair of ferromagnetic layers
Implementation Method 2
in a perpendicular magnetization type magnetoresistance effect element having magnetic anisotropy in a direction perpendicular to a film surface, various laminated structures are being studied in order to enhance the perpendicular magnetic anisotropy of a ferromagnetic layer
Data Source
AI summary
Provided is a magnetoresistance effect element configured by laminating a first electrode, a magnetization pinned layer having a fixed magnetization direction, a first insulating layer, a magnetization free layer having a variable magnetization direction, a second insulating layer, and a second electrode in order, in which the magnetization pinned layer includes a first magnetic body provided on the first electrode, and a second magnetic body provided on the first magnetic body via a non-magnetic metal layer, at least any of the first magnetic body and the second magnetic body is configured by providing a magnetic layer directly above a non-magnetic layer, and either the non-magnetic layer or the magnetic layer is formed in a multilayer structure in which different materials are alternately laminated.