Magnetoresistive Element Using Mo or W to Improve Thermal Stability

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Solution Overview

Problem

Existing magnetoresistive random access memory (MRAM) technologies face challenges in achieving high thermal stability and resistance variation rates without compromising perpendicular magnetic anisotropy and MR ratio, particularly when mixing materials like Cr or V with CoFeB.

Innovation Solution

Incorporating nonmagnetic Mo or W with CoFeB in the storage layer to reduce saturation magnetization without affecting perpendicular magnetic anisotropy or the MR ratio, thereby enhancing thermal stability and resistance variation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If Cr or V is mixed with CoFeB to reduce saturation magnetization, then thermal stability is improved, but perpendicular magnetic anisotropy and MR ratio deteriorate

Engineering Contradiction:

Improvethermal stabilityVSAvoidperpendicular magnetic anisotropy and MR ratio

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The invention changes the material composition parameter by using Mo or W (materials with higher standard electrode potentials) instead of Cr or V. This parameter change allows reduction of saturation magnetization while maintaining perpendicular magnetic anisotropy and MR ratio, resolving the technical contradiction between thermal stability and reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite magnetic layer by combining CoFeB with Mo or W. This composite material approach achieves the desired reduction in saturation magnetization for improved thermal stability while the specific choice of Mo or W preserves the perpendicular magnetic anisotropy and MR ratio, unlike Cr or V mixtures

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If saturation magnetization is reduced to increase thermal stability, then memory maintenance is improved, but MR ratio may be compromised

Engineering Contradiction:

Improvethermal stability and memory maintenanceVSAvoidMR ratio

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The invention changes the compositional parameter by selecting Mo or W over traditional Cr or V additives. This specific parameter change enables saturation magnetization reduction for better thermal stability and memory maintenance while the unique properties of Mo or W preserve the MR ratio, resolving the contradiction

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 approach allows for increased thermal stability and reliable memory maintenance in MRAM without reducing the MR ratio or perpendicular magnetic anisotropy, facilitating stable memory storage and improved reliability.

Implementation Method 1

a first magnetic layer; a nonmagnetic layer on the first magnetic layer; and a second magnetic layer on the nonmagnetic layer

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Implementation Method 2

without affecting perpendicular magnetic anisotropy

Methodology Applied

Scientific EffectMagnetic anisotropy: Anisotropy

Data Source

PatentUS10103318B2Magnetoresistive element

Publication Date: 2018.10.16 SK HYNIX INC

AI summary

According to one embodiment, there is provided a magnetoresistive element, including a first magnetic layer, a nonmagnetic layer on the first magnetic layer, and a second magnetic layer on the nonmagnetic layer, wherein one of the first and second magnetic layers include one of Co and Fe, and a material having a higher standard electrode potential than Co and Fe.