Magnetic Memory Element Composite Perpendicular Enhancement Layer
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Solution Overview
Problem
Spin transfer torque magnetic random access memory (STT-MRAM) devices face challenges in achieving thermal stability and cost-effective manufacturing as the size of perpendicular magnetic tunnel junctions (MTJs) is miniaturized, leading to degraded thermal stability and increased power consumption.
Innovation Solution
Incorporating a magnetic free layer structure with a first and second magnetic free layer separated by a perpendicular enhancement layer (PEL) and a magnetic reference layer structure with a first and second magnetic reference layer also separated by a PEL, along with optional anti-ferromagnetic coupling, tuning, or compensation layers to enhance perpendicular anisotropy and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of perpendicular magnetic tunnel junctions (MTJs) is miniaturized, then device scalability is improved, but thermal stability is degraded
Solution Approach 1:
The magnetic free layer is divided into multiple segments (first magnetic free layer, second magnetic free layer) separated by perpendicular enhancement layers. This segmentation allows each layer to contribute to thermal stability while the overall structure maintains miniaturization for scalability.
Solution Approach 2:
The patent employs composite magnetic layer structures combining different magnetic materials (CoFeB, CoFe, CoFeNi) with perpendicular enhancement layers (MgO, Ta, W) to achieve both high thermal stability and small device footprint for continued scaling.
2Productivity
If the size of perpendicular magnetic tunnel junctions (MTJs) is miniaturized, then device scalability is improved, but power consumption is increased
Solution Approach 1:
Dividing the magnetic free layer into multiple segments reduces the switching current required for each individual layer, thereby reducing overall power consumption while maintaining the miniaturized device structure for scalability.
Solution Approach 2:
The patent modifies magnetic layer parameters (composition, thickness, perpendicular anisotropy) to optimize the switching characteristics, enabling lower power consumption in miniaturized devices while maintaining scalability.
3Reliability
If composite perpendicular enhancement layer structure is implemented, then thermal stability is improved, but device complexity is increased
Solution Approach 1:
The complex perpendicular enhancement structure is segmented into distinct functional layers (MgO barrier, Ta/W enhancement layers) that can be independently optimized and manufactured, managing complexity through modular design.
Solution Approach 2:
The perpendicular enhancement layers serve multiple functions simultaneously: providing thermal stability, enabling perpendicular magnetization, and facilitating scalable manufacturing, thereby justifying the increased structural complexity.
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
The solution improves the thermal stability and scalability of STT-MRAM devices, reducing power consumption while maintaining effective data retention and manufacturing efficiency.
Implementation Method 1
enhance perpendicular anisotropy and thermal stability
Implementation Method 2
a first perpendicular enhancement layer (PEL) formed between the first and the second magnetic free layers
Implementation Method 3
separated from the magnetic reference layer structure by an anti-ferromagnetic coupling layer
Implementation Method 4
Spin transfer torque magnetic random access memory (STT-MRAM)
Data Source
AI summary
The present invention is directed to an MTJ memory element comprising a magnetic free layer structure including one or more magnetic free layers that have a variable magnetization direction substantially perpendicular to layer planes thereof; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure; a magnetic reference layer structure including a first magnetic reference layer and a second magnetic reference layer with a perpendicular enhancement layer interposed therebetween, the first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof; an anti-ferromagnetic coupling layer formed adjacent to the second magnetic reference layer; and a magnetic fixed layer formed adjacent to the anti-ferromagnetic coupling layer. The non-magnetic perpendicular enhancement layer includes a first perpendicular enhancement sublayer formed adjacent to the first magnetic reference layer and a second perpendicular enhancement sublayer formed adjacent to the second magnetic reference layer.