Spin Element High Resistance Layer Wiring Reliability

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Solution Overview

Problem

The existing spin elements face issues with electric potential concentration and wiring deterioration due to differences in resistivity between the wiring materials used for spin orbit torque type magnetoresistance effect elements and magnetic domain wall movement type magnetic recording elements, leading to potential degradation of the wiring.

Innovation Solution

A spin element design incorporating a laminated body with a first ferromagnetic layer, conductive parts, and high resistance layers with resistivity equal to or higher than the wiring, strategically positioned to reduce electric potential concentration and prevent wiring deterioration, including features like uneven interfaces and varying thicknesses to manage current distribution effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different wiring materials are used for spin orbit torque type magnetoresistance effect elements and magnetic domain wall movement type magnetic recording elements, then the spin element functionality is improved, but electric potential concentration and wiring deterioration occur due to resistivity differences

Engineering Contradiction:

Improvespin element functionalityVSAvoidelectric potential concentration and wiring deterioration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A high resistance layer is introduced as an intermediary component between the wiring and the magnetoresistance effect element. This layer acts as a buffer that equalizes the electrical potential difference caused by resistivity mismatch between different wiring materials, thereby preventing electric potential concentration and wiring deterioration while maintaining the functionality of spin elements with different wiring materials

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The high resistance layer is strategically positioned only at specific locations where wiring materials with different resistivities connect to the magnetoresistance effect element. This localized application addresses the resistivity mismatch problem only where it occurs, without affecting the overall performance of the spin elements

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If heavy metal wiring is used for spin orbit torque type magnetoresistance effect element, then spin injection efficiency is improved, but electromigration resistance deteriorates

Engineering Contradiction:

Improvespin injection efficiencyVSAvoidelectromigration resistance

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The high resistance layer serves as a protective intermediary between the heavy metal wiring and the magnetoresistance effect element. It reduces the current density in the heavy metal wiring by providing an additional resistance path, thereby decreasing electromigration stress on the wiring while preserving the spin injection efficiency needed for SOT-MRAM operation

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

The proposed spin element and reservoir element configuration effectively curb electric potential concentration and wiring deterioration, enhancing the reliability and longevity of the spin element by using high resistance layers to buffer electric potential differences and reduce electromigration.

Implementation Method 1

a first high resistance layer which is in contact with the wiring between the first conductive part and the wiring and has an electrical resistivity equal to or higher than that of the wiring

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

in the case of the spin orbit torque type magnetoresistance effect element, a heavy metal is often used for the wiring in order to inject many spins into a ferromagnetic layer

Methodology Applied

Scientific EffectSpin Hall Effect: Hall Effect

Implementation Method 3

A resistance value of the magnetoresistance effect element changes according to a difference in a relative angle between magnetization directions of two magnetic films

Methodology Applied

Scientific EffectMagnetoresistance Effect: Magnetoresistance

Data Source

PatentUS11545618B2Spin element and reservoir element including high resistance layer

Publication Date: 2023.01.03 TDK CORP

AI summary

A spin element includes a wiring, a laminated body including a first ferromagnetic layer laminated on the wiring, a first conductive part and a second conductive part which sandwich the first ferromagnetic layer in a plan view in a laminating direction, and a first high resistance layer which is in contact with the wiring between the first conductive part and the wiring and has an electrical resistivity equal to or higher than that of the wiring.