Magnetic Memory Stack Layout for Read Disturb Suppression
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Solution Overview
Problem
Memory devices with variable resistance struggle to achieve high storage capacity and data reading performance due to limitations in switching current distributions and read disturb issues across different memory cells.
Innovation Solution
The memory device incorporates a stacked structure of ferromagnetic layers with opposite magnetizations and a shift cancel layer, which allows for controlled switching currents and reduced read disturb by optimizing the read current direction and layer configurations, ensuring consistent data reading performance across cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a variable resistance element is used for data storage, then storage capacity can be increased, but data reading performance deteriorates due to switching current distribution limitations and read disturb issues
Solution Approach 1:
The memory cell is segmented into multiple ferromagnetic layers (first ferromagnetic layer, second ferromagnetic layer, third ferromagnetic layer) with distinct functions. The first and second ferromagnetic layers form the magnetic tunnel junction for data storage, while the third ferromagnetic layer acts as a shift cancel layer to compensate for read disturb effects. This segmentation allows independent optimization of storage capacity and reading performance.
Solution Approach 2:
Different regions of the memory cell have specialized properties: the first ferromagnetic layer has magnetization in a first direction, the second ferromagnetic layer has magnetization in a second direction (opposite to the first), and the third ferromagnetic layer has magnetization in a third direction (opposite to the second). This local quality differentiation enables precise control over switching currents and read disturb compensation in specific areas of the cell.
2Ease of operation
If ferromagnetic layers with opposite magnetizations are stacked, then switching current control is improved, but device complexity increases
Solution Approach 1:
The stack exhibits asymmetric magnetization directions: the first ferromagnetic layer and second ferromagnetic layer have opposite magnetizations, while the third ferromagnetic layer has magnetization opposite to the second layer. This asymmetric configuration creates distinct switching current characteristics that improve controllability while maintaining a manageable structural complexity through systematic layer arrangement.
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 enhances data reading performance and reduces read disturb, providing a consistent data reading margin and improved reliability across memory cells.
Implementation Method 1
a first ferromagnetic layer, a first insulating layer, a second ferromagnetic layer, a non-magnetic first metal layer, and a third ferromagnetic layer stacked in order from a side of the first conductor. The second ferromagnetic layer and the third ferromagnetic layer have magnetizations in opposite directions.
Implementation Method 2
A memory device that stores data using an element having a variable resistance is known.
Data Source
AI summary
A memory device includes a first conductor, a first stacked body on the first conductor, a second conductor on the first stacked body, a second stacked body on the second conductor, and a third conductor on the second stacked body. The first stacked body includes a first ferromagnetic layer, a first insulating layer, a second ferromagnetic layer, a non-magnetic first metal layer, and a third ferromagnetic layer stacked in order from a side of the first conductor. The second and third ferromagnetic layers have magnetizations in opposite directions. The second stacked body includes a fourth ferromagnetic layer, a second insulating layer, a fifth ferromagnetic layer, a non-magnetic second metal layer, and a sixth ferromagnetic layer stacked in order from a side of the second conductor. The fifth and sixth ferromagnetic layers have magnetizations in opposite directions. The sixth ferromagnetic layer has a larger volume than the third ferromagnetic layer.