MRAM Storage Element with Ferri-Pin Fixing Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to improve the thermal stability of magnetic random access memory (MRAM) while reducing the write current necessary for magnetization reversal, as existing MRAMs face issues with thermal stability and increased current requirements due to scaled-down element sizes.
Innovation Solution
A storage element with a magnetization fixing layer having a multilayered ferri-pin structure and an insulating layer between the storage and magnetization fixing layers, using Co—Fe—B as the ferromagnetic material, where spin-polarized electrons are injected to change the magnetization direction, reducing the effective diamagnetic field and maintaining sufficient thermal stability without increasing the write current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If element size is scaled down to increase memory density, then productivity and storage capacity improve, but thermal stability deteriorates and write current requirements increase
Solution Approach 1:
The magnetization fixing layer is divided into multiple sub-layers (first fixing layer, second fixing layer, third fixing layer) with different magnetization directions and coercive forces. This segmentation allows each layer to contribute differently to stabilizing the storage layer's magnetization, improving thermal stability even at scaled-down element sizes without increasing write current requirements
Solution Approach 2:
The patent employs a composite magnetic layer structure combining ferromagnetic materials with different magnetic properties (coercive forces and magnetization directions) in the magnetization fixing layer. This composite structure creates a synergistic effect that enhances thermal stability while maintaining low write current operation, resolving the contradiction between miniaturization and reliability
2Productivity
If element size is scaled down to increase memory density, then productivity improves, but write current requirements increase
Solution Approach 1:
The magnetization fixing layer is segmented into multiple sub-layers with progressively decreasing coercive forces from bottom to top. This segmentation creates a cascading magnetic field effect that efficiently reverses the storage layer's magnetization with lower current requirements, enabling high-density storage without increasing write current
Solution Approach 2:
The patent changes the magnetic parameters (coercive force, magnetization direction) of each sub-layer in the magnetization fixing layer to optimize the magnetization reversal process. By carefully controlling these parameters, the system achieves efficient writing at scaled dimensions without requiring proportionally higher currents
3Device complexity
If magnetization fixing layer uses single-layer structure, then device complexity is reduced, but thermal stability and magnetization control are insufficient
Solution Approach 1:
The magnetization fixing layer is segmented into multiple sub-layers, each with specific coercive forces and magnetization directions. This segmentation provides fine-grained control over the magnetic fields acting on the storage layer, enabling precise magnetization control and enhanced thermal stability despite the increased structural complexity
Solution Approach 2:
The patent introduces vertical stratification of magnetic properties within the magnetization fixing layer, creating a gradient structure where each sub-layer contributes differently to the overall magnetic control. This dimensional organization of magnetic properties enables superior control capabilities that compensate for the increased layer 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 reduces the write current required for magnetization reversal, enhances thermal stability, and strengthens perpendicular magnetic anisotropy, ensuring reliable operation and reduced power consumption in MRAM devices.
Implementation Method 1
the direction of the magnetization of the storage layer is changed by injecting spin-polarized electrons in a lamination direction of a layer structure having the storage layer, the insulating layer, and the magnetization fixing layer
Implementation Method 2
the magnetic storage element 103 has a storage layer a direction of whose magnetization is adapted to be reversed. Also, the magnetic storage element 103, for example, is composed of a magnetic tunnel junction element (MTJ element).
Implementation Method 3
the magnetic storage element 103, for example, is composed of a magnetic tunnel junction element (MTJ element)
Data Source
AI summary
Disclosed herein is a storage element, including: a storage layer which has magnetization vertical to a film surface and in which a direction of the magnetization is changed in correspondence to information; a magnetization fixing layer which has magnetization vertical to a film surface becoming a reference of the information stored in the storage layer, which is composed of plural magnetic layers, and which has a multilayered ferri-pin structure into which the plural magnetic layers are laminated one upon another through a non-magnetic layer(s); and an insulating layer made of a non-magnetic material and provided between the storage layer and the magnetization fixing layer.