Magnetoresistance Element for Neural Network Weight Storage

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Solution Overview

Problem

Current magnetoresistance effect elements for neural networks face challenges in reducing area, improving processing speed, and conserving power while maintaining high-speed writing capabilities.

Innovation Solution

A magnetoresistance effect element with a channel layer without net magnetization, a recording layer with switchable magnetization states, and a reference layer with fixed magnetization direction, connected through terminals for current pulses to control magnetization states and resistance for efficient neural network operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional magnetoresistance effect elements are used for neural networks, then high-speed writing capability is maintained, but area reduction, processing speed improvement, and power conservation are limited

Engineering Contradiction:

Improveprocessing speedVSAvoidelement area

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The magnetoresistance effect element is divided into functionally independent layers: a recording layer for storing neural network weights, a channel layer for current flow, and a reference layer for comparison. This segmentation allows each layer to be optimized independently, reducing overall area while maintaining high-speed writing capability through specialized material selection and structure design in each segment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a vertically stacked laminated structure where the channel layer, recording layer, and reference layer are nested in the vertical direction. This three-dimensional nesting approach reduces the planar area footprint of the element while preserving all necessary functional components, enabling area reduction without sacrificing processing speed or writing performance.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Area of stationary object

If magnetoresistance effect element size is reduced, then area is reduced, but maintaining high-speed writing and processing capabilities becomes difficult

Engineering Contradiction:

Improveelement areaVSAvoidpower consumption

Core Design Contradiction:

Area of stationary objectVSPower

Solution Approach 1:

The patent changes material parameters and structural dimensions of the recording layer and channel layer to achieve low-power operation in a compact form. By optimizing the thickness and composition of each layer, the element achieves efficient switching at lower current densities, reducing power consumption while maintaining small area and high-speed writing capability simultaneously.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If conventional structures are used, then manufacturing is straightforward, but area reduction and performance improvement are limited

Engineering Contradiction:

Improveprocessing speedVSAvoidstructure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent employs composite material structures in the recording layer and channel layer, combining multiple materials with complementary properties to achieve high-speed writing and low power consumption. This composite approach, while increasing material complexity, enables superior performance that outweighs the manufacturing complexity through standardized deposition processes for each material layer.

Inventive Principle:

Principle #40Composite materials

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

Enables the use of magnetoresistance effect elements in neural networks, reducing size, improving processing speed, and conserving power while maintaining high-speed writing capabilities.

Implementation Method 1

A magnetoresistance effect element includes: a channel layer that is formed from a material that does not have net magnetization

Methodology Applied

Scientific EffectMagnetoresistance effect: Magnetoresistance

Implementation Method 2

a recording layer which includes a film formed from a ferromagnetic material, of which a magnetization state is changed to one of two or greater magnetization states

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentUS11557719B2Magnetoresistance effect element, circuit device, and circuit unit

Publication Date: 2023.01.17 TOHOKU UNIV

AI summary

There is provided a magnetoresistance effect element includes: a channel layer that extends in a first direction; a recording layer which includes a film formed from a ferromagnetic material, of which a magnetization state is changed to one of two or greater magnetization states, and which is formed on the channel layer; a non-magnetic layer that is provided on a surface of the recording layer; a reference layer which is provided on a surface of the non-magnetic layer, which includes a film formed from a ferromagnetic material, and of which a magnetization direction is fixed; a terminal pair that includes a first terminal and a second terminal which are electrically connected to the channel layer with an interval in the first direction, and to which a current pulse for bringing the recording layer to any one magnetization state with a plurality of pulses is input by flowing a current to the channel layer between the first terminal and the second terminal; and a third terminal that is electrically connected to the reference layer.