Magnetic Memory Device Free Reversing Pattern
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Solution Overview
Problem
Conventional magnetic memory devices face challenges in achieving high integration due to complex fabrication processes, high power consumption, and the need for precise alignment, which also leads to increased planar area and difficulties in reducing the free layer size without losing stored data due to the super-paramagnetic limit.
Innovation Solution
A magnetic memory device is designed with an invariable pinning pattern and a variable pinning pattern on a substrate, where a tunnel barrier pattern is interposed between them, and a free reversing pattern is used to reverse the magnetization direction of the storage and guide free patterns, allowing for reduced power consumption and simplified fabrication without the need for a conventional digit line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional magnetic memory device uses a digit line and bit line configuration for programming, then data can be stored in the magnetic tunnel junction pattern, but the device requires precise alignment between lines and patterns, increases planar area, and complicates the fabrication process
Solution Approach 1:
The patent removes the digit line from the conventional magnetic memory device structure. Instead of using both digit lines and bit lines for programming, the invention uses only bit lines to apply magnetic fields for writing data, while reading is performed through the magnetic tunnel junction resistance change. This extraction of the digit line simplifies the fabrication process and reduces alignment requirements while maintaining data storage functionality
Solution Approach 2:
The bit line serves multiple functions in the patent: it is used for both writing data (by generating magnetic field through current) and for reading data (by measuring resistance change). This multi-functionality of the bit line eliminates the need for separate digit lines, reducing device complexity and fabrication difficulty
2Productivity
If the free layer size is reduced to increase integration density, then more memory cells can be integrated, but data is lost due to the super-paramagnetic limit
Solution Approach 1:
The patent introduces a gradient layer with gradually changing composition or thickness to modify the magnetic anisotropy energy distribution. This parameter change in the magnetic layer structure enhances the stability of small-sized free layers, allowing reduced dimensions without falling into the super-paramagnetic limit, thus maintaining data retention while increasing integration density
Solution Approach 2:
The patent employs composite magnetic layer structures including pinned layers, free layers, and gradient layers with different material compositions. These composite structures provide enhanced magnetic stability through exchange coupling and anisotropy engineering, enabling the free layer to maintain stable magnetization states even at reduced sizes for higher integration
3Manufacturing precision
If precise alignment is implemented between bit line, digit line, and magnetic tunnel junction pattern, then proper magnetic field application is achieved, but the fabrication process becomes more complex and time-consuming
Solution Approach 1:
By removing the digit line structure entirely, the patent eliminates the need for aligning digit lines with magnetic tunnel junction patterns. Only bit lines need to be aligned, which significantly reduces the number of alignment steps and improves fabrication efficiency while maintaining sufficient manufacturing precision
4Reliability
If a conventional digit line configuration is used for programming, then magnetic fields can be generated for data storage, but power consumption increases due to the need for driving the digit line
Solution Approach 1:
The patent removes the digit line to reduce power consumption. By using only bit lines for both read and write operations, the device eliminates the power required to drive digit lines, achieving lower overall power consumption while maintaining programming capability through optimized bit line current paths
Solution Approach 2:
The bit line is designed to perform both write (program) and read functions. During writing, the bit line carries high current to generate magnetic field; during reading, it carries low current to measure resistance. This multi-functionality consolidates the electrical paths, eliminating redundant digit line power consumption
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 design enables high integration, reduces power consumption, and simplifies the fabrication process by eliminating the need for precise alignment and peripheral circuits, while overcoming the super-paramagnetic limit by maintaining data integrity with reduced planar area.
Implementation Method 1
A free reversing pattern is interposed between the storage and guide free patterns. The free reversing pattern reverses a magnetization direction of the storage free pattern and a magnetization direction of the guide free pattern in the opposite directions.
Implementation Method 2
A pinned pattern is interposed between the invariable pinning pattern and the tunnel barrier pattern. The pinned pattern has a magnetization direction pinned by the invariable pinning pattern.
Data Source
AI summary
A magnetic memory device is provided. The magnetic memory device includes an invariable pinning pattern and a variable pinning pattern on a substrate. A tunnel barrier pattern is interposed between the invariable pinning pattern and the variable pinning pattern, and the pinned pattern is interposed between the invariable pinning pattern and the tunnel barrier pattern. A storage free pattern is interposed between the tunnel barrier pattern and the variable pinning pattern, and a guide free pattern is interposed between the storage free pattern and the variable pinning pattern. A free reversing pattern is interposed between the storage and guide free patterns. The free reversing pattern reverses a magnetization direction of the storage free pattern and a magnetization direction of the guide free pattern in the opposite directions.