MRAM Free Layer With Doped Metal Insertion Layers

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Solution Overview

Problem

Current magnetoresistive random access memory (MRAM) devices face challenges in maintaining resistance and current distribution at high temperatures and improving spin transfer torque efficiency, with existing structures prone to oxygen and crystalline material diffusion affecting their performance.

Innovation Solution

The MRAM device incorporates a free layer structure with multiple magnetic layers and non-magnetic metal insertion layers doped with magnetic materials, spaced apart to prevent diffusion and enhance magnetic exchange coupling, along with a perpendicular magnetic anisotropy configuration, which includes a pinned layer, tunnel barrier layer, and an upper oxide layer to maintain electron spin and improve heat endurance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal insertion layers are used between magnetic layers, then magnetic exchange coupling is enhanced, but oxygen and crystalline material diffusion occurs affecting performance

Engineering Contradiction:

Improvemagnetic exchange couplingVSAvoidoxygen and crystalline material diffusion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A non-magnetic metal layer is introduced as an intermediary between the magnetic layer and the upper oxide layer. This intermediary layer prevents direct contact and diffusion between oxygen/crystalline materials and the metal insertion layer, while still allowing magnetic exchange coupling to occur through the thin non-magnetic barrier.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The structure combines multiple materials with different properties: magnetic layers for magnetization, non-magnetic metal insertion layers for exchange coupling, and non-magnetic metal barrier layers for diffusion prevention. This composite structure achieves both magnetic coupling and diffusion protection simultaneously.

Inventive Principle:

Principle #40Composite materials

2Productivity

If multiple magnetic layers are stacked closely, then spin transfer torque efficiency is improved, but heat generation increases affecting stability

Engineering Contradiction:

Improvespin transfer torque efficiencyVSAvoidheat generation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The free layer is segmented into multiple thin magnetic layers separated by non-magnetic metal insertion layers. This segmentation allows each magnetic layer to be thinner, improving spin transfer torque efficiency, while the non-magnetic layers act as thermal barriers to reduce heat accumulation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the structure have different thermal properties. The non-magnetic metal insertion layers have lower thermal conductivity compared to the magnetic layers, creating localized thermal management zones that dissipate heat while maintaining magnetic coupling in the magnetic layers.

Inventive Principle:

Principle #3Local quality

3Reliability

If metal insertion layers are doped with magnetic material, then magnetic properties are enhanced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvemagnetic propertiesVSAvoiddoping concentration control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The doping concentration in the non-magnetic metal layers is optimized to a specific range that provides sufficient magnetic enhancement without requiring extreme manufacturing precision. By adjusting the doping level to an optimal parameter, the structure achieves good magnetic properties with manufacturable tolerances.

Inventive Principle:

Principle #35Parameter changes

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 MRAM device's heat endurance, resistance distribution, and current flow, reducing switching currents and improving spin transfer torque efficiency while maintaining excellent magnetic properties.

Implementation Method 1

non-magnetic metal insertion layers between adjacent ones of the plurality of magnetic layers... prevent diffusion

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

first magnetic layer having perpendicular magnetic anisotropy... second magnetic layer having perpendicular magnetic anisotropy... third magnetic layer having perpendicular magnetic anisotropy

Methodology Applied

Scientific EffectPerpendicular magnetic anisotropy: Anisotropy

Implementation Method 3

enhance magnetic exchange coupling

Methodology Applied

Scientific EffectMagnetic exchange coupling: Magnetism

Implementation Method 4

tunnel barrier layer on the pinned layer

Methodology Applied

Scientific EffectTunnel barrier: Electrical Resistance

Implementation Method 5

improving spin transfer torque efficiency... reducing switching currents

Methodology Applied

Scientific EffectSpin transfer torque:

Data Source

PatentUS12190928B2Magnetoresistive random access memory device having a metal layer doped with a magnetic material

Publication Date: 2025.01.07 SAMSUNG ELECTRONICS CO LTD

AI summary

A magnetoresistive random access memory device includes a pinned layer; a tunnel barrier layer on the pinned layer; a free layer structure on the tunnel barrier layer, the free layer structure including a plurality of magnetic layers and a plurality of metal insertion layers between the magnetic layers; and an upper oxide layer on the free layer structure, wherein each of the metal insertion layers includes a non-magnetic metal material doped with a magnetic material, and the metal insertion layers are spaced apart from each other.