Magnetic Memory Device Layer Architecture for Storage Density
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Solution Overview
Problem
Current magnetic memory devices face limitations in increasing storage density due to challenges in optimizing the structure and materials used in magnetic layers and nonmagnetic layers, which affect the magnetic tunnel junctions and overall device performance.
Innovation Solution
The magnetic memory device incorporates a conductive layer with specific metal portions, separated magnetic layers, and nonmagnetic layers with regions of Mg and oxygen/nitrogen, along with insulating regions of Si and Al, to enhance storage density by controlling magnetization and reducing residual stress through careful layer alignment and material selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If magnetic layers are made thinner to increase storage density, then storage density increases, but magnetic signal strength and stability deteriorate
Solution Approach 1:
The patent uses composite magnetic layer structures with specific material combinations (CoFeB, CoFe, Ta, MgO) to maintain magnetic signal strength while reducing layer thickness. The composite structure of multiple thin layers with different magnetic and nonmagnetic properties enables both high storage density and reliable magnetic signaling.
Solution Approach 2:
The patent applies different materials and thicknesses to different regions of the magnetic layers. Specifically, the first and second magnetic layers have different compositions (CoFeB vs CoFe) and different thickness ranges, with local optimization of magnetic properties to maintain signal stability while achieving overall high density.
2Quantity of substance
If magnetic layer thickness is reduced to increase storage density, then storage density increases, but recording current requirements increase
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: magnetic layer thickness (5-20 nm range), material composition (CoFeB, CoFe, Ta, MgO ratios), and layer stacking sequence. These parameter changes enable reduced recording current while maintaining high storage density through enhanced spin-torque efficiency in the optimized structure.
Solution Approach 2:
The composite structure with alternating magnetic and nonmagnetic layers (CoFeB/Ta/MgO/CoFe) creates favorable spin scattering conditions that reduce the current required for magnetization switching, enabling high density with lower recording currents.
3Quantity of substance
If more magnetic layers are added to increase storage density, then storage density increases, but device complexity increases
Solution Approach 1:
The patent divides the magnetic memory structure into segmented functional units: reference layers, free layers, barrier layers, and capping layers. Each segment has a specific function, allowing complex high-density storage to be achieved through modular repetition of these standardized segments rather than monolithic complex structures.
Solution Approach 2:
The patent employs universal layer designs that serve multiple functions. For example, the Ta layers serve both as spacer layers for magnetic decoupling and as oxidation barriers, while MgO layers function as both tunnel barriers and protective capping layers, reducing overall device complexity through multi-functional elements.
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 increases storage density by maintaining effective surface areas of magnetic layers, reducing leakage currents, and allowing for more stable recording operations with reduced recording current, thereby improving the overall performance of the magnetic memory device.
Implementation Method 1
The conductive layer includes a first metal and is configured to supply a current. The first magnetic layer is separated from a third portion of the conductive layer... The controller is configured to supply a current to the conductive layer
Implementation Method 2
The first nonmagnetic layer includes a first region and a second region... The second region overlaps at least a portion of the second magnetic layer in the second direction... reducing residual stress through careful layer alignment and material selection
Implementation Method 3
The first magnetic layer is separated from the third portion in a first direction crossing a second direction... The second magnetic layer is provided between the first magnetic layer and at least a portion of the third portion
Data Source
AI summary
According to one embodiment, a magnetic memory device includes a conductive layer, first and second magnetic layers, a first nonmagnetic layer and a controller. The conductive layer includes first and second portions, and a third portion between the first and second portions. The first magnetic layer is separated from the third portion in a first direction crossing a second direction being from the first portion toward the second portion. The second magnetic layer is provided between the first magnetic layer and at least a portion of the third portion. The first nonmagnetic layer includes first and second regions. The first region is provided between the first and second magnetic layers. The second region is continuous with the first region. The second region overlaps at least a portion of the second magnetic layer in the second direction. The controller is electrically connected to the first and second portions.