MTJ Memory Stray Field Correction via External Permanent Magnets
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Solution Overview
Problem
Existing semiconductor memory devices with Magnetic Tunnel Junction (MTJ) structures face challenges due to the need for a magnetic correction layer that increases fabrication time and cost, and can generate non-uniform leakage magnetic fields, affecting switching characteristics.
Innovation Solution
Incorporating permanent magnets external to the MTJ structure to provide a correction magnetic field, reducing the need for a built-in magnetic correction layer and allowing for a more uniform and effective magnetic field correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic correction layer is integrated into the MTJ structure, then the stray field influence is corrected, but the fabrication time and cost increase
Solution Approach 1:
The patent divides the magnetic correction function into separate external permanent magnets positioned above and below the MTJ structure, rather than integrating it as a single correction layer within the MTJ stack. This segmentation allows the correction function to be implemented independently, reducing fabrication complexity and time while maintaining the ability to correct stray field influences on the free layer.
Solution Approach 2:
The patent introduces external permanent magnets as intermediary elements that mediate the magnetic field correction. These permanent magnets generate opposing magnetic fields to counteract the stray fields from the pinned layer, acting as intermediaries between the pinned layer and the free layer to achieve field uniformity without requiring integration into the MTJ structure itself.
2Reliability
If a magnetic correction layer is integrated into the MTJ structure, then the stray field influence is corrected, but the fabrication complexity and cost increase
Solution Approach 1:
The correction function is segmented into separate external permanent magnets positioned above and below the MTJ structure. This segmentation eliminates the need to integrate correction layers during the complex MTJ fabrication process, thereby reducing fabrication complexity and cost while maintaining effective stray field correction.
Solution Approach 2:
The magnetic correction function is extracted from the MTJ structure itself and implemented as separate external permanent magnets. This extraction removes the correction layer integration step from the fabrication process, simplifying the overall device fabrication while preserving the necessary magnetic field correction functionality.
3Reliability
If a built-in magnetic correction layer is used, then the stray field is corrected, but non-uniform leakage magnetic fields are generated
Solution Approach 1:
The patent applies local quality by positioning permanent magnets at specific locations above and below the MTJ structure to create localized magnetic field corrections. This allows tailored magnetic field distribution that can be optimized for uniformity across the free layer, avoiding the non-uniform leakage fields that arise from integrated correction layers.
Solution Approach 2:
Instead of adding a correction layer within the MTJ structure that reinforces the stack architecture, the patent inverts the approach by placing correction elements externally on opposite sides. This inverted configuration allows magnetic fields to converge uniformly onto the free layer from both directions, achieving better field uniformity than conventional integrated correction methods.
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 improves the switching characteristics of the MTJ structure, reduces fabrication complexity and costs, and enhances the performance of semiconductor memory devices by providing a controlled magnetic field correction without the limitations of a built-in correction layer.
Implementation Method 1
a magnetic field generated by the first permanent magnet may have a direction which offsets or reduces an influence of a stray field generated by the pinned layer
Data Source
AI summary
In one implementation, an electronic device is provided to include a semiconductor memory, wherein the semiconductor memory may include: a variable resistance element including a Magnetic Tunnel Junction (MTJ) structure including a free layer having a changeable magnetization direction free layer, a pinned layer having a fixed magnetization direction and a tunnel barrier layer interposed between the free layer and the pinned layer, and the electronic device may further include, in a first direction in which the free layer, the tunnel barrier layer and the pinned layer are arranged, a first permanent magnet having a first surface facing a first surface of the variable resistance element and spaced from the variable resistance element, wherein a magnetic field generated by the first permanent magnet may have a direction which offsets or reduces an influence of a stray field generated by the pinned layer.