3D Magnetic Memory Device Domain Wall Control
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Solution Overview
Problem
Existing racetrack-type magnetic memory devices face challenges in controlling stable magnetic domain wall movement and achieving high integration density, particularly in forming notches at constant intervals along the vertical direction.
Innovation Solution
A magnetic memory device with a three-dimensional (3D) structure featuring a magnetic track layer having a bottom notch and sidewall notches, along with a mold structure with protrusions, which facilitates stable magnetic domain wall movement and improves integration intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a racetrack-type magnetic memory device is used, then information storage is achieved through magnetic domain wall movement, but stable control of magnetic domain wall movement and high integration density are difficult to achieve
Solution Approach 1:
The patent transitions from a conventional planar racetrack structure to a vertical three-dimensional structure. The magnetic track layer is positioned vertically above the reading unit, with notches formed at specific heights along the vertical direction. This dimensional change enables better control over magnetic domain wall movement through the notches while allowing higher integration density by stacking components vertically rather than horizontally
Solution Approach 2:
The magnetic track layer is segmented by forming notches at specific positions along its length. These notches divide the continuous magnetic track into distinct segments, creating controlled regions for magnetic domain wall movement. The notches are formed by removing portions of the magnetic track layer at predetermined locations, enabling precise control over domain wall behavior while maintaining the overall track structure
2Manufacturing precision
If notches are formed at constant intervals along the vertical direction, then magnetic domain wall movement can be controlled, but manufacturing precision and structural complexity increase
Solution Approach 1:
The patent employs a mold structure positioned at the bottom of the magnetic track layer to preliminarily define the positions where notches will be formed. The mold structure includes protrusions that extend upward, and these protrusions serve as templates for subsequent notch formation. By preparing the mold structure in advance, the positions and intervals of notches are predetermined, simplifying the manufacturing process and ensuring constant interval spacing
Solution Approach 2:
The mold structure acts as an intermediary element between the manufacturing process and the final magnetic track layer structure. The mold structure with its protrusions provides a physical template that guides the formation of notches at constant intervals. This intermediary structure simplifies the direct patterning process by providing pre-defined positions for notch formation, thereby reducing manufacturing 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 3D structure allows for easy adjustment of magnetic domain wall movement and enhances integration density, overcoming the difficulties in controlling domain wall movement and achieving high integration in racetrack-type memory devices.
Implementation Method 1
The magnetic track layer includes a free layer, a spin orbit torque (SOT) inducing layer, and a seed capping layer that are sequentially stacked in a thickness direction of the magnetic track layer
Data Source
AI summary
A magnetic memory device includes a reading unit on a substrate, a magnetic track layer on the reading unit, the magnetic track layer including a bottom portion between first and second sidewall portions, and a mold structure on the bottom portion of the magnetic track layer, and between the first and second sidewall portions. The mold structure includes first and second mold layers alternately arranged in a first direction perpendicular to a top surface of the substrate, and the magnetic track layer includes magnetic domains and magnetic domain walls between magnetic domains, the first and second sidewall portions of the magnetic track layer including sidewall notches corresponding to the magnetic domain walls, and the bottom portion includes a bottom notch corresponding to one of the magnetic domain walls.