Pt-Ru Exchange Coupling for MRAM Reference Layer Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic random access memory (MRAM) elements face challenges in maintaining robustness and stability of the magnetization of the reference layer over time and varying conditions, affecting data retention and endurance.
Innovation Solution
Incorporating a synthetic antiferromagnetic structure with an extended magnetic proximity effect using Pt layers adjacent to a Ru exchange coupling layer, enhancing antiferromagnetic exchange coupling and pinning of the reference layer's magnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional reference layer structure is used in MTJ elements, then the device complexity is low, but the magnetic stability and pinning robustness of the reference layer deteriorates over time and varying conditions
Solution Approach 1:
The patent applies composite materials by creating a synthetic antiferromagnetic structure composed of multiple magnetic layers (first magnetic layer, second magnetic layer) coupled through an antiparallel exchange coupling layer. This composite structure combines the properties of individual layers to achieve enhanced magnetic stability and pinning robustness that cannot be obtained with a single reference layer, directly resolving the contradiction between reliability and complexity.
Solution Approach 2:
The reference layer is segmented into multiple distinct magnetic layers (first magnetic layer and second magnetic layer) separated by an antiparallel exchange coupling layer. This segmentation allows each layer to contribute differently to the overall magnetic properties, with the first layer providing perpendicular magnetic anisotropy and the second layer providing in-plane magnetization, thereby improving magnetic stability while managing structural complexity through functional division.
2Reliability
If the antiferromagnetic exchange coupling is weakened, then the device complexity is reduced, but the data retention and endurance of the MRAM element deteriorates
Solution Approach 1:
The patent utilizes parameter changes by controlling the thickness of the antiparallel exchange coupling layer and the magnetic layer thicknesses to optimize the antiferromagnetic exchange coupling strength. By adjusting these dimensional parameters during fabrication, the coupling strength can be tuned to achieve the desired data retention and endurance without unnecessarily increasing structural complexity, as the same basic structure can accommodate different thickness parameters.
3Stability of the object's composition
If the reference layer pinning is not sufficiently robust, then the manufacturing process is simpler, but the magnetic orientation stability under varying conditions deteriorates
Solution Approach 1:
The patent applies local quality by creating distinct magnetic properties in different regions of the reference layer structure. The first magnetic layer is designed with perpendicular magnetic anisotropy localized at its interface with the tunnel barrier, while the second magnetic layer has in-plane magnetization. This local differentiation of magnetic properties within the pinning structure enhances overall magnetic orientation stability without requiring uniform complexity throughout the entire structure.
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 approach significantly improves the magnetic stability and retention of the reference layer, enhancing data endurance and robustness in MRAM elements by extending the range of antiferromagnetic coupling and maintaining magnetic anisotropy without reducing coercivity.
Implementation Method 1
The antiparallel exchange coupling structure includes a layer of Ru located between first and second layers of Pt. The first and second magnetic structures are exchange coupled with the magnetic reference layer. The synthetic antiferromagnetic structure includes first and second magnetic structures and an antiparallel exchange coupling structure located between the first and second magnetic structures.
Implementation Method 2
Incorporating a synthetic antiferromagnetic structure with an extended magnetic proximity effect using Pt layers adjacent to a Ru exchange coupling layer, enhancing antiferromagnetic exchange coupling and pinning of the reference layer's magnetization.
Data Source
AI summary
A magnetic memory element for Magnetic Random Access Memory. The magnetic memory element has improved reference layer magnetic pinning. The magnetic memory element has a magnetic free layer, a magnetic reference layer and a non-magnetic barrier layer located between the magnetic free layer and the magnetic reference layer. The magnetic reference layer has a magnetic moment that is pinned in a perpendicular orientation through exchange coupling with a synthetic antiferromagnetic structure that includes first and second magnetic structures and an antiferromagnetic exchange coupling structure located between the first and second magnetic structures. The antiferromagnetic exchange coupling structure includes a layer of Ru located between first and second layers of Pt. The Pt layers in the antiferromagnetic exchange coupling structure advantageously increases the magnetic proximity effect at both Ru interfaces, which extends the exchange coupling range of the antiferromagnetic exchange coupling layer.