Magnetic Memory Devices with Perpendicular and In-Plane Structures

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Solution Overview

Problem

Magnetic memory devices face challenges in achieving improved thermal stability and reduced writing current, especially as they are scaled down in size, which affects their performance and efficiency.

Innovation Solution

The magnetic memory device incorporates a perpendicular magnetic structure, a free magnetic pattern with a switchable magnetization direction, and an in-plane magnetic structure with antiferromagnetically coupled first and second magnetic patterns, which reduces the stray field and switching current, thereby enhancing thermal stability and reducing the threshold current required for switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If magnetic memory devices are scaled down in size, then device density and integration are improved, but thermal stability deteriorates and writing current increases

Engineering Contradiction:

Improvedevice sizeVSAvoidthermal stability

Core Design Contradiction:

Area of moving objectVSReliability

Solution Approach 1:

The patent changes the magnetization direction parameter from in-plane to perpendicular magnetization. This parameter change enables smaller device sizes while maintaining thermal stability because perpendicular magnetization provides higher energy barrier for thermal fluctuations, allowing scaling down without sacrificing reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite magnetic structures combining multiple magnetic layers with different properties (pinned layer, free layer, antiferromagnetic layer). This composite approach allows optimization of both thermal stability and switching characteristics independently, resolving the contradiction between device size reduction and thermal stability maintenance

Inventive Principle:

Principle #40Composite materials

2Area of moving object

If magnetic memory devices are scaled down in size, then device density is improved, but writing current increases

Engineering Contradiction:

Improvedevice sizeVSAvoidwriting current

Core Design Contradiction:

Area of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent changes the magnetization switching mechanism parameter from field-induced to spin-transfer torque (STT). This parameter change reduces writing current because STT directly transfers angular momentum to switch magnetization without requiring large magnetic fields, enabling efficient switching in scaled-down devices

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the magnetic field-based switching mechanism with a spin-current-based mechanism. This substitution eliminates the need for high current loops generating magnetic fields, reducing writing current requirements while maintaining effective magnetization switching in miniaturized devices

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If conventional magnetic memory structures are used, then device simplicity is maintained, but thermal stability and switching efficiency cannot be simultaneously optimized

Engineering Contradiction:

Improvestructure simplicityVSAvoidthermal stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the magnetic structure into distinct functional layers (pinned layer, tunnel barrier, free layer, antiferromagnetic layer). This segmentation allows independent optimization of each layer's properties to achieve both thermal stability and efficient switching, while the overall structure remains relatively simple and manufacturable

Inventive Principle:

Principle #1Segmentation

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 thermal stability of the magnetic memory device and decreases the switching current, enabling more efficient operation and scalability.

Implementation Method 1

a tunnel barrier pattern between the perpendicular magnetic structure and the free magnetic pattern

Methodology Applied

Scientific EffectQuantum tunneling:

Implementation Method 2

The in-plane magnetic structure may include a first magnetic pattern, a second magnetic pattern on the first magnetic pattern, and a non-magnetic pattern between the first and second magnetic patterns. The first and second magnetic patterns may be antiferromagnetically coupled to each other by the non-magnetic pattern

Methodology Applied

Scientific EffectAntiferromagnetic coupling:

Data Source

PatentUS11588100B2Magnetic memory devices including magnetic tunnel junctions

Publication Date: 2023.02.21 SAMSUNG ELECTRONICS CO LTD

AI summary

A magnetic memory device may include a perpendicular magnetic structure, an in-plane magnetic structure, a free magnetic pattern between the perpendicular magnetic structure and the in-plane magnetic structure, and a tunnel barrier pattern between the perpendicular magnetic structure and the free magnetic pattern. The perpendicular magnetic structure may include at least one pinned pattern which has a perpendicular magnetization direction that is pinned to a specific direction, and the free magnetic pattern may have a switchable perpendicular magnetization direction. The in-plane magnetic structure may include a first magnetic pattern and a second magnetic pattern, and each of the first and second magnetic patterns may have a different respective in-plane magnetization direction.