Oxygen-Deficient Magnetic Tunnel Junctions for Fast Low-Resistance Switching

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Solution Overview

Problem

Existing magnetic tunneling junction devices face challenges in maintaining low resistance and high durability while achieving fast operation speeds due to issues with oxygen and nitrogen diffusion affecting the free layer, which increases resistance and decreases switching efficiency.

Innovation Solution

The manufacturing method involves forming a first oxide layer with a stoichiometrically oxygen-deficient composition, using a cryogenic cooling process, and incorporating a wetting layer to trap oxygen and nitrogen atoms, thereby preventing their diffusion into the free layer, and using metal elements with high oxygen affinity to dope the second magnetic layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional manufacturing methods are used without oxygen-deficient oxide layer, then manufacturing process is simpler, but oxygen and nitrogen diffuse into free layer causing increased resistance and decreased switching efficiency

Engineering Contradiction:
Improveswitching efficiencyVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The oxide layer is prepared with an oxygen-deficient composition before the free layer is formed. This preliminary action creates a protective environment that prevents oxygen and nitrogen diffusion into the free layer during subsequent manufacturing steps, thereby maintaining low resistance and high switching efficiency without requiring complex post-processing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The oxide layer with oxygen-deficient composition acts as an intermediary barrier between the external environment and the free layer. This intermediary structure traps oxygen and nitrogen atoms, preventing them from reaching and degrading the free layer, thus protecting the device performance while maintaining manufacturing feasibility

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If cryogenic cooling process is used to form oxide layer, then oxygen and nitrogen diffusion is prevented improving resistance stability, but manufacturing process becomes more complex and time-consuming

Engineering Contradiction:
Improveresistance stabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The oxide layer is formed with specific compositional parameters (oxygen-deficient stoichiometry) rather than relying solely on temperature control. This parameter change allows the layer to inherently resist oxygen and nitrogen diffusion at standard manufacturing temperatures, achieving resistance stability without requiring continuous cryogenic cooling during fabrication

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The oxide layer is prepared in advance with the correct oxygen-deficient composition before subsequent manufacturing steps. This preliminary preparation ensures that the layer has the necessary properties to prevent diffusion during later processing, reducing the need for complex temperature control measures during fabrication

Inventive Principle:
Principle #10Preliminary action

3Reliability

If metal elements with high oxygen affinity are not used to dope second magnetic layer, then doping process is simpler, but perpendicular magnetic anisotropy and switching efficiency are reduced

Engineering Contradiction:
Improveswitching efficiencyVSAvoiddoping process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Metal elements with high oxygen affinity (such as Fe, Co, Ni, or their alloys) are introduced into the second magnetic layer to modify its magnetic properties. This compositional parameter change enhances perpendicular magnetic anisotropy and switching efficiency by promoting favorable magnetic moment alignment and interaction with the oxide layer

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The second magnetic layer is formed as a composite material combining magnetic metals (Fe, Co, Ni, or their alloys) with the oxide layer. This composite structure leverages the high oxygen affinity of the metal elements to strengthen magnetic coupling and perpendicular anisotropy, achieving improved switching efficiency through material composition rather than complex processing

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

This approach enhances the stability and operation speed of the magnetic tunneling junction device by maintaining low resistance and reducing the likelihood of resistance area increase, improving switching efficiency and perpendicular magnetic anisotropy.

Implementation Method 1

the oxide layer having a stoichiometrically oxygen-deficient composition may trap oxygen and/or nitrogen atoms

Methodology Applied
Scientific EffectOxygen trapping: Absorption (physical)

Implementation Method 2

the oxide layer having a stoichiometrically oxygen-deficient composition may trap oxygen and/or nitrogen atoms

Methodology Applied
Scientific EffectNitrogen trapping: Absorption (physical)

Implementation Method 3

incorporating a wetting layer to trap oxygen and nitrogen atoms, thereby preventing their diffusion into the free layer

Methodology Applied
Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 4

The oxygen affinity of the metal element of the second magnetic layer may be greater than that of the magnetic material of the second magnetic layer

Methodology Applied
Scientific EffectOxygen affinity: Chemical Bonding

Implementation Method 5

The resistance of a magnetic tunneling junction device varies with the magnetization direction of a free layer

Methodology Applied
Scientific EffectMagnetoresistance: Magnetoresistance

Data Source

PatentEP4053925B1Magnetic tunneling junction device, memory device including the same, and method of manufacturing the magnetic tunneling junction device
Publication Date: 2026.04.22 SAMSUNG ELECTRONICS CO LTD
  • EP4053925B1 patent drawingFigure 1~2A
  • EP4053925B1 patent drawingFigure 2B~2C
  • EP4053925B1 patent drawingFigure 2D~2E

AI summary

Provided are magnetic tunneling junction devices, memory devices including the magnetic tunneling junction devices, and methods of manufacturing the magnetic tunneling junction devices. The magnetic tunneling junction device (200) includes a first magnetic layer (201); a second magnetic layer (205) disposed to face the first magnetic layer; and a first oxide layer (202) disposed between the first magnetic layer and the second magnetic layer and including a metal oxide, wherein the metal oxide of the first oxide layer has a stoichiometrically oxygen-deficient composition, and wherein the second magnetic layer includes a magnetic material doped with a metal element.