MTJ Seed Layer Structure for Heat-Stable Pinned Layer Crystallinity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing magnetic tunneling junction devices face challenges in maintaining performance during high temperature heat treatment processes, which can lead to deterioration of the device characteristics.

Innovation Solution

The magnetic tunneling junction device incorporates a seed layer with a double or triple layer structure, where one or more layers include rhenium (Re) and ruthenium (Ru), to enhance the crystal quality and stability of the pinned layer, thereby improving the device's resistance-area product (RA) and tunnel magnetoresistance ratio (TMR).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional single-layer seed layer is used, then the device structure is simple, but the device deteriorates during high temperature heat treatment

Engineering Contradiction:

Improvedevice stability during heat treatmentVSAvoidseed layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The seed layer is divided into multiple sub-layers (first seed layer, second seed layer, and optionally third seed layer), where each layer has specific thickness and material composition. This segmentation allows different layers to perform specialized functions, with total thickness controlled at 1-10 nm to prevent deterioration during heat treatment while maintaining structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The seed layer uses composite material structure combining different materials in specific layers. This composite approach enhances the overall stability and performance of the magnetic tunneling junction device during high temperature heat treatment processes, resolving the contradiction between reliability and structural complexity.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If the seed layer thickness is increased, then the crystal quality improves, but the device performance deteriorates due to excessive thickness

Engineering Contradiction:

Improvecrystal qualityVSAvoiddevice performance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The total thickness of the seed layer is precisely controlled within the range of 1 nm to 10 nm. This parameter optimization ensures sufficient crystal quality for device performance while preventing deterioration caused by excessive thickness. The multi-layer structure allows achieving this precise thickness control with improved manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250127061A1Magnetic tunneling junction device and memory device including the same

Publication Date: 2025.04.17 SAMSUNG ELECTRONICS CO LTD

AI summary

A magnetic tunnel junction device and a memory device including the magnetic tunnel junction device are provided. The magnetic tunnel junction device includes a seed layer, a pinned layer on the seed layer, a free layer facing the pinned layer, and a tunnel barrier layer between the pinned layer and the free layer, wherein the seed layer includes a first seed layer and a second seed layer between the first seed layer and the pinned layer, and one of the first seed layer and the second seed layer includes rhenium (Re) and the other of the first seed layer and the second seed layer includes ruthenium (Ru).