Lateral Current Storage Element for Low Power Magnetic Memory

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Solution Overview

Problem

Magnetoresistance effect elements in magnetic memory devices experience increased power consumption due to high read currents, which can lead to reduced lifespan and efficiency.

Innovation Solution

A storage element design featuring a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic layer, with a wiring system and electrode configuration that allows for efficient current flow without the need for current to be passed in the stacking direction, utilizing a spin-orbit torque mechanism to reduce power consumption and extend element lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a read current is passed in the stacking direction of the magnetoresistance effect element, then data can be read from the element, but the power consumption increases and the element lifespan decreases

Engineering Contradiction:

Improveelement lifespanVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the current flow direction from the vertical stacking direction to a lateral direction by introducing a conductive layer that contacts the lateral side surface of the ferromagnetic layer. This dimensional change allows read current to flow without passing through the stacking direction, reducing power consumption and extending element lifespan while maintaining data read capability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If a write current is passed in the stacking direction to control magnetization directions, then data can be written, but the magnetoresistance effect element characteristics deteriorate

Engineering Contradiction:

Improvedata writing capabilityVSAvoidelement characteristics

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent enables write current to flow in a lateral direction through the conductive layer rather than in the stacking direction. This dimensional change allows magnetization control without deteriorating element characteristics, as the write current now flows through a different path that does not stress the magnetoresistance effect element structure

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Productivity

If high read current is applied to magnetoresistance effect elements in magnetic memory, then data reading is achieved, but heat generation increases and efficiency decreases

Engineering Contradiction:

Improvedata reading efficiencyVSAvoidheat generation

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent introduces a lateral current path through the conductive layer that contacts the lateral side surface, changing the current flow from vertical to lateral direction. This reduces resistance and heat generation during read operations, improving energy efficiency while maintaining data reading capability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The conductive layer acts as an intermediary structure that enables current to flow laterally between electrodes without passing through the magnetoresistance effect element stacking direction. This mediator reduces direct current stress on the element, lowering heat generation and improving read efficiency

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 solution enables low power consumption and extended lifespan of magnetoresistance effect elements by optimizing current paths and reducing heat generation, thereby improving the reliability and efficiency of magnetic memory devices.

Implementation Method 1

An SOT is induced by a spin current generated by a spin-orbit interaction or a Rashba effect at an interface between different materials

Methodology Applied

Scientific EffectSpin-orbit interaction:

Implementation Method 2

An SOT is induced by a spin current generated by a spin-orbit interaction or a Rashba effect at an interface between different materials

Methodology Applied

Scientific EffectRashba effect:

Implementation Method 3

A giant magnetoresistance (GMR) element constituted by a multilayer film of a ferromagnetic layer and a nonmagnetic layer

Methodology Applied

Scientific EffectGiant magnetoresistance (GMR): Magnetoresistance

Implementation Method 4

a tunnel magnetoresistance (TMR) element using an insulating layer (a tunnel barrier layer or a barrier layer) as a nonmagnetic layer

Methodology Applied

Scientific EffectTunnel magnetoresistance (TMR): Magnetoresistance

Data Source

PatentUS11974507B2Storage element, semiconductor device, magnetic recording array, and method of manufacturing storage element

Publication Date: 2024.04.30 TDK CORP

AI summary

A storage element includes a first ferromagnetic layer; a second ferromagnetic layer; a nonmagnetic layer interposed between the first ferromagnetic layer and the second ferromagnetic layer in a first direction; a first wiring that extends in a second direction different from the first direction and together with the nonmagnetic layer sandwiches the first ferromagnetic layer in the first direction; and an electrode that together with the nonmagnetic layer sandwiches the second ferromagnetic layer in at least a part in the first direction, wherein the electrode is in contact with at least a part of a lateral side surface of the second ferromagnetic layer.