Magnetic Memory Sidewall Boron Diffusion

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Solution Overview

Problem

Magnetic memory devices with boron in the storage and reference layers face detrimental effects due to boron accumulation at interfaces and damage layers formed during etching, affecting the properties of the magnetoresistive element.

Innovation Solution

A method involving thermal treatment and oxidation to diffuse boron into sidewall insulating layers, preventing its accumulation at interfaces and mitigating damage layer issues, while using a stacked structure with crystallized magnetic layers and a tunnel barrier layer to enhance the magnetoresistive element's performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If boron is present in the storage layer and reference layer to enhance magnetic properties, then the magnetoresistive element's performance is improved, but boron accumulates at interfaces with the tunnel barrier layer causing detrimental effects

Engineering Contradiction:

Improvemagnetoresistive element performanceVSAvoidboron accumulation at interface

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A sidewall insulating layer containing boron is introduced as an intermediary between the stacked structure and the external environment. This layer acts as a boron sink, capturing and containing boron that diffuses during thermal treatment, preventing its accumulation at the tunnel barrier layer interfaces while maintaining the magnetic properties of the storage and reference layers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful boron atoms are extracted from the interface region between the magnetic layers and tunnel barrier layer, and relocated into the sidewall insulating layer. This extraction process removes the detrimental factor from the critical interface area while preserving the functional boron content in the magnetic layers.

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of manufacture

If etching process is used to form the pattern of the stacked structure, then the device structure is formed, but a damage layer is created on the side surface negatively affecting magnetoresistive element properties

Engineering Contradiction:

Improvepattern formationVSAvoidmagnetoresistive element properties

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The sidewall insulating layer, which contains boron, is positioned to cover the damage layer formed on the side surface during etching. The boron-containing material in the sidewall layer compensates for and repairs the damaged regions, converting the harmful damage layer into a beneficial structure with improved properties.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Thermal treatment is applied to change the physical and chemical parameters of the damage layer and sidewall insulating layer. This thermal processing modifies the material properties, allowing boron diffusion into the sidewall layer and repair of the damage layer, thereby improving the magnetoresistive element properties.

Inventive Principle:

Principle #35Parameter changes

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 approach prevents boron-induced property reduction in magnetoresistive elements by diffusing boron into sidewall insulating layers, maintaining the integrity of the magnetic memory device's performance and functionality.

Implementation Method 1

A method involving thermal treatment and oxidation to diffuse boron into sidewall insulating layers

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

A method involving thermal treatment and oxidation to diffuse boron into sidewall insulating layers

Methodology Applied

Scientific EffectThermal treatment: Heat Treatment

Implementation Method 3

A method involving thermal treatment and oxidation to diffuse boron into sidewall insulating layers

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS10490732B2Magnetic memory device with sidewall layer containing boron and manufacturing method thereof

Publication Date: 2019.11.26 KIOXIA CORP

AI summary

According to one embodiment, a magnetic memory device includes a stacked structure including a first magnetic layer, a second magnetic layer and a nonmagnetic layer between the first magnetic layer and the second magnetic layer, and a sidewall insulating layer provided on a side surface of the stacked structure and containing boron (B).