Magnetoresistive Device Offset Layer Jc Reduction
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Solution Overview
Problem
Conventional spin transfer torque magnetic random access memory (STT-MRAM) designs face limitations in storage density due to high critical switching current density (Jc) and its distribution, primarily caused by the small angle between the magnetizations of the free layer and reference layer, which is affected by thermal fluctuations and fabrication process variations.
Innovation Solution
A magnetoresistive device is designed with a fixed magnetic layer, a free magnetic layer, and an offsetting magnetic layer, where the latter's magnetization is oriented non-parallel to the easy axes of the former two, allowing for a pre-set angle between the free and reference layers to reduce Jc and improve its distribution, achieved through a specific stack structure and layer arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the magnetizations of the free layer and reference layer are aligned along the same easy axis, then the device structure is simple, but the critical switching current density is high and storage density is limited
Solution Approach 1:
The reference layer is segmented into two distinct magnetic layers: a first magnetic layer with magnetization along a first easy axis, and a second magnetic layer with magnetization along a second easy axis that is non-parallel to the first. This segmentation allows the device to achieve lower critical switching current density while maintaining structural organization.
Solution Approach 2:
The invention introduces an additional dimension to the magnetic layer structure by adding a second magnetic layer with magnetization oriented along a non-parallel easy axis. This dimensional expansion in magnetic orientation space enables improved switching characteristics without compromising device functionality.
2Ease of manufacture
If the angle between magnetizations of free layer and reference layer is small, then the device fabrication is easier, but the critical switching current density distribution is large due to thermal fluctuation and initial angle variation
Solution Approach 1:
By segmenting the reference layer into two magnetic layers with different easy axes, the invention reduces sensitivity to thermal fluctuations and initial angle variations. Each layer contributes differently to the overall magnetic switching, resulting in a narrower Jc distribution and improved manufacturing precision.
Solution Approach 2:
The invention changes the magnetic parameters by introducing a second easy axis orientation that is non-parallel to the first. This parameter change in magnetization orientation fundamentally alters the switching characteristics, reducing Jc distribution width while maintaining ease of manufacture.
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 effectively reduces the critical switching current density and improves its uniformity, enhancing the storage density and reliability of STT-MRAM devices by offsetting the magnetizations of the free and reference layers.
Implementation Method 1
an offsetting magnetic layer structure having a magnetization orientation along an axis at least substantially non-parallel to at least one of the first easy axis or the second easy axis
Data Source
AI summary
According to embodiments of the present invention, a magnetoresistive device is provided. The magnetoresistive device includes a fixed magnetic layer structure having a fixed magnetization orientation along a first easy axis, a free magnetic layer structure having a variable magnetization orientation along a second easy axis, and an offsetting magnetic layer structure having a magnetization orientation along an axis at least substantially non-parallel to at least one of the first easy axis or the second easy axis, wherein the fixed magnetic layer structure, the free magnetic layer structure and the offsetting magnetic layer structure are arranged one over the other. According to further embodiments of the present invention, a method of forming a magnetoresistive device is also provided.