Segmented Shift Cancelling Layer for Magnetic Memory Field Control

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Solution Overview

Problem

In magnetic memory devices with perpendicular magnetization, the magnetic field applied from the reference layer to the storage layer is difficult to effectively cancel, especially in miniaturized devices, due to challenges in processing thick shift cancelling layers.

Innovation Solution

A shift cancelling layer with a first insulating region and multiple conductive, magnetic second regions is used, which increases the magnetic field on the storage layer without requiring patterning, allowing for effective cancellation of the magnetic field and maintaining electrical insulation and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the shift cancelling layer is thickened to effectively cancel the magnetic field from the reference layer, then the magnetic field cancellation effectiveness is improved, but the processing difficulty increases significantly due to miniaturization requirements

Engineering Contradiction:

Improvemagnetic field cancellation effectivenessVSAvoidprocessing difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The shift cancelling layer is divided into a stacked structure with multiple layers having different magnetic saturation characteristics. The first shift cancelling layer has lower magnetic saturation than the second shift cancelling layer, allowing each layer to contribute differently to field cancellation and enabling effective cancellation with reduced overall thickness, thus resolving the contradiction between cancellation effectiveness and processing ease.

Inventive Principle:

Principle #1Segmentation

2Productivity

If the MTJ element is miniaturized for high integration, then the device density is improved, but the processing of thick shift cancelling layers becomes extremely difficult

Engineering Contradiction:

Improvedevice integration densityVSAvoidprocessing difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

By segmenting the shift cancelling layer into multiple thinner layers with different magnetic properties, the patent enables miniaturization of MTJ elements while maintaining manufacturability. The stacked structure allows effective field cancellation without requiring a single thick layer, thus supporting high integration density while preserving ease of manufacture.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses composite magnetic layers with different saturation characteristics stacked together. This composite structure provides the functionality of a thick cancellation layer while using thinner individual layers that are easier to process in miniaturized devices, resolving the contradiction between device density and manufacturing ease.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If the shift cancelling layer is made thinner to ease processing, then the processing difficulty is reduced, but the magnetic field cancellation effectiveness deteriorates

Engineering Contradiction:

Improveprocessing easeVSAvoidmagnetic field cancellation effectiveness

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The segmentation of the shift cancelling layer into multiple layers with different magnetic saturations allows each thin layer to contribute to field cancellation in a complementary manner. The first layer with lower saturation addresses certain field components while the second layer with higher saturation addresses others, achieving effective cancellation despite reduced individual layer thickness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the shift cancelling structure have different magnetic properties - the first shift cancelling layer has lower magnetic saturation while the second has higher saturation. This local differentiation of magnetic quality allows the thin stacked structure to achieve comprehensive field cancellation that would require a much thicker uniform layer, thus resolving the contradiction between processing ease and cancellation effectiveness.

Inventive Principle:

Principle #3Local quality

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 enables efficient cancellation of the magnetic field from the reference layer to the storage layer, facilitating high-performance magnetic memory devices with improved processing ease and electrical properties.

Implementation Method 1

a magnetic memory device which uses a magnetoresistance effect element (a magnetic tunnel junction (MTJ) element) exhibiting perpendicular magnetization

Methodology Applied

Scientific EffectPerpendicular magnetization: Magnetism

Implementation Method 2

a magnetic memory device which uses a magnetoresistance effect element (a magnetic tunnel junction (MTJ) element)

Methodology Applied

Scientific EffectMagnetoresistance effect: Magnetoresistance

Data Source

PatentUS9236563B2Magnetic memory device and method of manufacturing the magnetic memory device

Publication Date: 2016.01.12 KIOXIA CORP

AI summary

According to one embodiment, a magnetic memory device includes a magnetoresistance effect element having a structure in which a first magnetic layer, a nonmagnetic layer, a second magnetic layer, and a third magnetic layer are stacked, wherein the third magnetic layer comprises a first region and a plurality of second regions, and each of the second regions is surrounded by the first region, has conductivity, and has a greater magnetic property than the first region.