SOT-MRAM Cell Side-by-Side Layer Switching
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Solution Overview
Problem
Conventional SOT-MRAM devices require additional conditions such as external magnetic fields or spin transfer torque to switch the magnetic moment of the perpendicular magnetic anisotropy (PMA) storage layer due to symmetric switching limitations.
Innovation Solution
A SOT-MRAM cell design featuring a magnetic storage layer disposed side by side and in contact with a SOT layer, where the SOT layer generates torque that allows switching of the magnetic storage layer by reversing the electrical current direction without additional conditions, utilizing materials like platinum, tantalum, or metal alloys for the SOT layer and ferromagnetic materials for the storage and reference layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a perpendicular magnetic anisotropy (PMA) magnetic storage layer is used in SOT-MRAM, then the magnetic moment can be oriented perpendicular to the substrate plane for stable data storage, but the spin polarization generated by spin-orbit coupling becomes orthogonal to the magnetic moment, creating symmetric switching that prevents effective switching without additional conditions
Solution Approach 1:
The patent introduces an asymmetric exchange bias field through an antiferromagnetic layer that creates an energy asymmetry between parallel and anti-parallel magnetic states. This asymmetric field breaks the symmetric switching barrier, allowing the spin-orbit torque to effectively switch the magnetic moment from one stable state to another without requiring additional external magnetic fields or complex conditions
2Reliability
If conventional SOT-MRAM structures are used with PMA materials, then reliable data storage is achieved, but additional conditions such as external magnetic fields or spin transfer torque from additional structures are required to switch the magnetic moment
Solution Approach 1:
The patent merges the spin-orbit torque layer with the magnetic storage layer in a side-by-side contact configuration, allowing direct interaction between the spin-polarized electrons and the magnetic moment. This integrated structure eliminates the need for separate external magnetic field generation systems or additional spin transfer torque structures, reducing device complexity while maintaining reliable data storage
Solution Approach 2:
The patent introduces an antiferromagnetic layer as an intermediary that generates an exchange bias field. This intermediary component mediates the interaction between the spin-orbit torque and the PMA magnetic storage layer, enabling effective switching by creating an asymmetric energy landscape that facilitates transitions between magnetic states without requiring complex external conditions
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
Enables switching of the magnetic storage layer without external assistance, improving the operational efficiency and reliability of SOT-MRAM devices by leveraging the spin-orbit coupling for symmetric switching.
Implementation Method 1
A SOT is generated by the electrical current flowing along the SOT layer due to the strong spin-orbit coupling of the SOT layer
Data Source
AI summary
Implementations of the present disclosure generally relate to a memory device. More specifically, implementations described herein generally relate to a SOT-MRAM. The SOT-MRAM includes a memory cell having a magnetic storage layer disposed side by side and in contact with a SOT layer. The side by side magnetic storage layer and the SOT layer can achieve the switching of the magnetic storage layer by reversing the direction of the electrical current flowing through the SOT layer without any additional conditions.