SOT-MTJ MRAM Cap Structure for Better Insulation and Smaller Area

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Solution Overview

Problem

Existing magnetoresistive random access memory (MRAM) devices face issues such as high chip area, high cost, high power consumption, limited sensitivity, and susceptibility to temperature variations.

Innovation Solution

A method for fabricating MRAM devices involving the formation of a spin orbit torque (SOT) layer, a magnetic tunneling junction (MTJ), and a cap layer with specific angled surfaces to enhance insulation and reduce chip area and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If conventional MRAM device structures are used, then data storage functionality is achieved, but chip area is large and manufacturing cost is high

Engineering Contradiction:

Improvechip areaVSAvoidmanufacturing cost

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent utilizes the spin orbit torque (SOT) effect which operates in a different dimensional approach compared to conventional current-through-MTJ methods. By introducing a separate SOT layer adjacent to the MTJ structure, the patent achieves magnetization switching through spin current generated in the SOT layer, enabling more compact device design and reducing chip area while maintaining functionality

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the device into functionally distinct segments: a magnetic tunneling junction (MTJ) for data storage and a separate spin orbit torque (SOT) layer for magnetization switching. This segmentation allows each component to be optimized independently and enables more efficient space utilization, reducing overall chip area and manufacturing complexity

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If conventional MRAM device structures are used, then data storage functionality is achieved, but power consumption is high

Engineering Contradiction:

Improvepower consumptionVSAvoidenergy efficiency

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent replaces the conventional electrical current switching mechanism with a spin-based mechanism. Instead of using high-current electrical switching through the MTJ, the patent employs spin current generated in the SOT layer to induce magnetization switching, significantly reducing power consumption and improving energy efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The SOT layer acts as an intermediary that converts charge current into spin current, which then acts on the MTJ to switch magnetization. This intermediary mechanism enables low-power operation by decoupling the high-current switching requirement from the data storage layer, reducing overall power consumption

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If conventional MRAM device structures are used, then data storage functionality is achieved, but insulation capabilities are insufficient

Engineering Contradiction:

Improveinsulation capabilityVSAvoidelectrical interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a non-magnetic barrier layer as an intermediary between the SOT layer and the MTJ structure. This barrier layer provides electrical isolation and insulation, preventing unwanted current leakage and electrical interference while maintaining the spin current coupling necessary for SOT switching functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs thin film barrier layers with optimized thickness and material composition to provide effective electrical insulation. These thin film structures achieve sufficient insulation capability while maintaining device compactness and not compromising the spin-orbit coupling efficiency

Inventive Principle:

Principle #30Flexible shells and thin films

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 method improves insulation capabilities and reduces chip area and power consumption, addressing the limitations of existing MRAM devices.

Implementation Method 1

a spin orbit torque (SOT) layer on a substrate

Methodology Applied

Scientific EffectSpin orbit torque (SOT):

Implementation Method 2

Magnetoresistance (MR) effect has been known as a kind of effect caused by altering the resistance of a material through variation of outside magnetic field

Methodology Applied

Scientific EffectMagnetoresistance (MR) effect: Magnetoresistance

Data Source

PatentUS20260013142A1Semiconductor device and method for fabricating the same

Publication Date: 2026.01.08 UNITED MICROELECTRONICS CORP

AI summary

A method for fabricating a magnetoresistive random access memory (MRAM) device includes the steps of first forming a spin orbit torque (SOT) layer on a substrate, forming a magnetic tunneling junction (MTJ) on the SOT layer, and then forming a first cap layer on the MTJ and the SOT layer. Preferably, a first angle included by a top surface of the SOT layer and a top surface of the first cap layer includes an acute angle.