Magnetic Tunnel Junction Metallic Ring Shunt Low Series Resistance
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Solution Overview
Problem
Magnetic tunnel junctions (MTJs) face challenges in achieving low series resistance, which affects their operating voltage and read speeds due to the separation of the free magnetization layer from conductive features, increasing resistance and limiting their efficiency.
Innovation Solution
Incorporating a metallic ring as a shunt resistor surrounding the top tunnel barrier of the MTJ structure, providing a low-resistance channel for electrons from the top free layer to the top electrode without disturbing the perpendicular magnetic anisotropy, and forming a magnetization enhancement stack with a second tunnel junction layer, metal contact layer, and metal electrode layer to enhance magnetic anisotropy and reduce series resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the free magnetization layer is separated from conductive features to maintain perpendicular magnetic anisotropy, then magnetic anisotropy is preserved, but series resistance increases
Solution Approach 1:
The conductive path is segmented into two parts: the tunnel junction path for spin-polarized current and the metallic ring path for charge current. This segmentation allows the free layer to remain separated from direct conductive contact (preserving magnetic anisotropy) while still providing a low-resistance current path through the metallic ring shunt.
Solution Approach 2:
The metallic ring acts as an intermediary element that provides a low-resistance shunt path for electrons. It mediates between the requirement for low series resistance and the need to maintain perpendicular magnetic anisotropy by offering an alternative current path that does not require direct contact between the free layer and conductive features.
2Use of energy by moving object
If a metallic ring shunt is added to reduce series resistance, then operating voltage decreases, but device complexity increases
Solution Approach 1:
The metallic ring is merged with the existing magnetization enhancement stack structure. The ring is formed as part of the same deposition and patterning sequence, combining the shunt function with the magnetic enhancement structure rather than adding a completely separate component.
Solution Approach 2:
The metallic ring structure serves multiple functions: it provides a low-resistance shunt path, maintains perpendicular magnetic anisotropy by avoiding direct contact with the free layer, and can be integrated with the magnetization enhancement stack. This multi-functionality reduces the need for additional separate components.
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 metallic ring structure significantly reduces the series resistance of the MTJ, enabling lower operating voltages and faster read speeds by providing a low-resistance pathway while maintaining perpendicular magnetic anisotropy, thus enhancing the overall efficiency of the MTJ.
Implementation Method 1
The metallic ring that functions as a shunt resistor provides a low resistance channel for electrons to travel from the top free layer of the magnetic tunnel junction (MTJ) to the top electrode
Implementation Method 2
two thin ferromagnetic layers separated by a thin insulating layer through which electrons can tunnel
Implementation Method 3
without disturbing the perpendicular magnetic anisotropy characteristics of the magnetic tunnel junction (MTJ) structure
Data Source
AI summary
An electrical device structure including a magnetic tunnel junction structure having a first tunnel junction dielectric layer positioned between a free magnetization layer and a fixed magnetization layer. A magnetization enhancement stack present on the magnetic tunnel junction structure. The magnetization enhancement stack includes a second tunnel junction layer that is in contact with the free magnetization layer of the magnetic tunnel junction structure, a metal contact layer present on the second tunnel junction layer, and a metal electrode layer present on the metal contact layer. A metallic ring on a sidewall of the magnetic enhancement stack, wherein a base of the metallic ring may be in contact with the free magnetization layer of the magnetic tunnel junction structure.