Magnetoresistive Element Boron Diffusion Control

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Solution Overview

Problem

Current magnetic storage devices with magnetoresistive effect elements face challenges in achieving high perpendicular magnetic anisotropy and tunnel magnetoresistive ratio (TMR ratio) due to limitations in annealing temperature and material diffusion, which affect the performance and reliability of the magnetoresistive effect elements.

Innovation Solution

The magnetic storage device incorporates a magnetoresistive effect element with a specific layer structure, including a ferromagnetic layer, non-magnetic layers such as rare-earth oxide and ruthenium or molybdenum, which enhances the perpendicular magnetic anisotropy and TMR ratio by controlling boron diffusion and crystallization during annealing at relatively lower temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature annealing is applied to improve perpendicular magnetic anisotropy and TMR ratio, then magnetic performance is enhanced, but material diffusion and degradation occur

Engineering Contradiction:

Improveperpendicular magnetic anisotropyVSAvoidmaterial diffusion

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

A non-magnetic layer comprising rare-earth oxide is introduced between the ferromagnetic layer and the capping layer to act as a diffusion barrier. This intermediary layer prevents boron diffusion from the capping layer into the ferromagnetic layer during annealing, while still allowing the annealing process to enhance perpendicular magnetic anisotropy and TMR ratio in the magnetoresistive effect element.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 improves the perpendicular magnetic anisotropy and TMR ratio, maintaining high performance while reducing the risk of degradation from high-temperature annealing, thus enhancing the overall efficiency and reliability of the magnetoresistive effect elements.

Implementation Method 1

a magnetoresistive effect element

Methodology Applied

Scientific EffectMagnetoresistive effect: Magnetoresistance

Implementation Method 2

controlling boron diffusion and crystallization during annealing

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

crystallization during annealing at relatively lower temperatures

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS11462680B2Magnetic storage device

Publication Date: 2022.10.04 KIOXIA CORP

AI summary

A magnetic storage device includes a magnetoresistive effect element. The magnetoresistive effect element includes a first ferromagnetic layer; a second ferromagnetic layer; a non-magnetic layer between the first ferromagnetic layer and the second ferromagnetic layer; and a first layer provided at a side of the first ferromagnetic layer opposite to a side of the first ferromagnetic layer at which the non-magnetic layer is provided. The first layer includes a rare-earth element and the first layer has a region including boron (B) at a proportion higher than a proportion of boron (B) in the first ferromagnetic layer.