Magnetic Tunnel Junctions With Segmented Recording Electrode
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Solution Overview
Problem
Boron present at the CoFe/MgO interface in magnetic tunnel junctions undesirably reduces tunneling magnetoresistance (TMR), which is a critical performance metric.
Innovation Solution
The magnetic tunnel junction design includes multiple non-magnetic insulator metal oxide layers within the magnetic recording material to increase the number of perpendicular magnetic anisotropy generating interfaces, enhancing the energy barrier while maintaining a similar or slightly higher critical switching current, thereby improving the Eb/Ic ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple non-magnetic insulator metal oxide layers are added within the magnetic recording material, then the energy barrier is increased and Eb/Ic ratio is improved, but the device complexity increases
Solution Approach 1:
The magnetic recording material is segmented into multiple magnetic regions separated by non-magnetic insulator metal oxide layers. This segmentation creates multiple perpendicular magnetic anisotropy generating interfaces, which increases the energy barrier and improves tunneling magnetoresistance while maintaining a manageable critical switching current
Solution Approach 2:
The invention uses composite material structure combining magnetic regions with non-magnetic insulator metal oxide layers (such as MgO) to create a multilayered magnetic recording material. This composite structure generates perpendicular magnetic anisotropy at the interfaces, enhancing the energy barrier without requiring excessive switching current
2Reliability
If the energy barrier is increased by adding multiple insulator layers, then the Eb/Ic ratio is improved, but the manufacturing complexity increases
Solution Approach 1:
The magnetic recording material is divided into multiple magnetic regions separated by thin non-magnetic insulator metal oxide layers. This segmentation approach allows for controlled deposition processes that can be integrated into existing manufacturing workflows, achieving high energy barrier through repeated thin-layer deposition rather than single complex layers
Solution Approach 2:
The invention changes the structural parameters of the magnetic recording material by introducing multiple interfaces with non-magnetic insulator metal oxide layers. This parameter change (from single-layer to multilayer structure) increases the perpendicular magnetic anisotropy and energy barrier while maintaining compatibility with standard deposition techniques
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 increases the energy barrier and maintains a comparable critical switching current, enhancing the Eb/Ic ratio and thus improving the tunneling magnetoresistance of the magnetic tunnel junction.
Implementation Method 1
A spin-polarized current is one with significantly more electrons of either spin. By passing a current through certain magnetic material (sometimes also referred to as polarizer material), one can produce a spin-polarized current. If a spin-polarized current is directed into a magnetic material, spin angular momentum can be transferred to that material, thereby affecting its magnetization orientation.
Implementation Method 2
The insulator material is sufficiently thin such that electrons can tunnel from one magnetic electrode to the other through the insulator material under appropriate conditions. Electrical resistance between those two nodes through the reference electrode, insulator material, and the recording electrode is dependent upon the magnetization direction of the recording electrode relative to that of the reference electrode.
Implementation Method 3
Crystallization of the CoFe can occur during or after deposition of the MgO by annealing the substrate at a temperature of at least about 250° C. This will induce the diffusion of B atoms out of the CoFe matrix being formed to allow crystallization into bcc 001 CoFe. Bcc 001 MgO acts as a template during the crystallization of CoFe.
Data Source
AI summary
A magnetic tunnel junction has a conductive first magnetic electrode comprising magnetic recording material. A conductive second magnetic electrode is spaced from the first electrode and comprises magnetic reference material. A non-magnetic tunnel insulator material is between the first and second electrodes. The magnetic recording material of the first electrode comprises a first magnetic region, a second magnetic region spaced from the first magnetic region, and a third magnetic region spaced from the first and second magnetic regions. A first non-magnetic insulator metal oxide-comprising region is between the first and second magnetic regions. A second non-magnetic insulator metal oxide-comprising region is between the second and third magnetic regions. Other embodiments are disclosed.