Magnetic Memory Conductive Layer Thickness Optimization
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Solution Overview
Problem
Magnetic memory devices using magnetoresistive effect elements face challenges in reducing write current, which can lead to increased current density and potential disconnection issues in the wiring portion, and decreased current density in the cell portion, affecting data storage efficiency.
Innovation Solution
The magnetic memory device incorporates a conductive layer with distinct portions that do not overlap with the magnetoresistive effect elements, ensuring a thicker film thickness in the wiring portion compared to the cell portion, reducing the risk of disconnection and write current increase by using a stacked structure of conductive layers with varying resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the film thickness of the conductive layer is increased to reduce resistance, then the write current decreases, but the current density in the cell portion decreases affecting data storage efficiency
Solution Approach 1:
The conductive layer is designed with non-uniform thickness: thicker in the wiring portion (first and third portions) to reduce resistance and prevent disconnection, and thinner in the cell portion (second portion) to maintain sufficient current density for data storage. This local variation in thickness optimizes both wiring reliability and storage efficiency simultaneously.
2Device complexity
If a single-layer conductive structure is used, then the device complexity is reduced, but the wiring portion may experience disconnection and increased resistance
Solution Approach 1:
The conductive layer is segmented into multiple portions with different thicknesses: a first portion, a second portion overlapping the cell, and a third portion. This segmentation allows each portion to be optimized for its specific function - the thicker first and third portions provide mechanical strength and low resistance for wiring, while the thinner second portion ensures adequate current density for the magnetoresistive effect element.
3Manufacturing precision
If the conductive layer thickness is uniform, then the manufacturing precision is simplified, but the resistance distribution becomes unfavorable for both wiring and cell operations
Solution Approach 1:
The conductive layer implements local quality variation through controlled thickness differences across different regions. The first and third portions have greater thickness to minimize resistance and prevent wiring disconnection, while the second portion has reduced thickness to maintain appropriate current density for the magnetoresistive effect element, optimizing overall device performance.
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 lowers the resistance of the wiring portion compared to the cell portion, preventing disconnection and minimizing the write current, thereby enhancing data storage efficiency and reliability.
Implementation Method 1
A magnetic memory device using a magnetoresistive effect element as a storage element is known.
Implementation Method 2
as a method for writing data without directly flowing a current into the magnetoresistive effect element, a writing method using spin orbit torque is known.
Data Source
AI summary
According to one embodiment, there is provided a magnetic memory device including a first conductive layer; and a first magnetoresistive effect element and a second magnetoresistive effect element that each extends in a first direction, are provided apart from each other in a second direction crossing the first direction, and are each in contact with the first conductive layer, wherein the first conductive layer includes a first portion that does not overlap with any of the first magnetoresistive effect element and the second magnetoresistive effect element when viewed in the first direction, a second portion that overlaps with a central region of the first magnetoresistive effect element when viewed in the first direction, and a third portion that overlaps with an edge region of the first magnetoresistive effect element when viewed in the first direction.