MRAM MTJ Contact Structure for Scalable Memory Integration

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current magnetic random access memory (MRAM) devices face limitations in scalability and integration due to the complexity of manufacturing processes and material compatibility, which affects the reliability and performance of magnetic tunnel junction (MTJ) cells.

Innovation Solution

The development of a semiconductor device with a magnetic tunnel junction (MTJ) cell structure that includes a specific configuration of ferromagnetic layers, tunneling barrier layers, and insulating layers, optimized for efficient electron tunneling and reduced resistance, using materials like magnesium oxide and cobalt-iron-boron, and employing advanced deposition methods such as physical vapor deposition and molecular beam epitaxy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex manufacturing processes are used to create MTJ cells, then device performance can be improved, but manufacturing complexity and integration difficulty increase

Engineering Contradiction:

ImproveMTJ cell performanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The MTJ cell structure is segmented into distinct functional layers (ferromagnetic layers, tunneling barrier, insulating layers) that can be manufactured separately and then integrated. This segmentation allows each layer to be optimized independently while simplifying the overall manufacturing process through modular assembly approaches.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite material structures combining ferromagnetic materials (cobalt-iron-boron), insulating materials (magnesium oxide), and other functional materials in layered configurations. These composite structures achieve superior MTJ performance while enabling standardized manufacturing processes for each material type.

Inventive Principle:

Principle #40Composite materials

2Reliability

If advanced deposition methods are used to optimize electron tunneling, then device performance improves, but manufacturing complexity increases

Engineering Contradiction:

Improveelectron tunneling efficiencyVSAvoiddeposition process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent optimizes electron tunneling efficiency by precisely controlling deposition parameters such as layer thickness (e.g., 3-5 nm for tunneling barriers), material composition ratios, and deposition temperatures. These parameter optimizations achieve high performance while using standard deposition techniques rather than requiring advanced specialized processes.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If material compatibility is ensured through strict selection, then device reliability improves, but manufacturing flexibility decreases

Engineering Contradiction:

Improvematerial compatibilityVSAvoidmanufacturing flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent selects materials with universal compatibility characteristics that can be integrated across different manufacturing platforms and process technologies. The chosen material system (ferromagnetic layers with magnesium oxide barriers) can be manufactured using conventional semiconductor fabrication processes, providing both reliability and manufacturing flexibility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances the performance and reliability of MRAM devices by improving data storage capabilities and reducing power consumption, while also simplifying the manufacturing process and ensuring compatibility of materials, leading to faster access times and minimal degradation over time.

Implementation Method 1

An MRAM cell is formed by a magnetic tunneling junction (MTJ) comprising two ferromagnetic layers which are separated by a thin insulating barrier, and operates by tunneling of electrons between the two ferromagnetic layers through the insulating barrier.

Methodology Applied

Scientific EffectElectron tunneling:

Implementation Method 2

employing advanced deposition methods such as physical vapor deposition and molecular beam epitaxy

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

employing advanced deposition methods such as physical vapor deposition and molecular beam epitaxy

Methodology Applied

Scientific EffectMolecular beam epitaxy: Epitaxy

Data Source

PatentUS11805658B2Magnetic random access memory and manufacturing method thereof

Publication Date: 2023.10.31 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

In a method of manufacturing a semiconductor device, a magnetic random access memory (MRAM) cell structure is formed. The MRAM cell structure includes a bottom electrode, a magnetic tunnel junction (MTJ) stack and a top electrode. A first insulating cover layer is formed over the MRAM cell structure. A second insulating cover layer is formed over the first insulating cover layer. An interlayer dielectric (ILD) layer is formed. A contact opening in the ILD layer is formed, thereby exposing the second insulating cover layer. A part of the second insulating cover layer and a part of the first insulating cover layer are removed, thereby exposing the top electrode. A conductive layer is formed in the opening contacting the top electrode.