Magnetic Tunnel Junction Stray Field Reduction
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Solution Overview
Problem
Existing memory devices face challenges in achieving optimal switching characteristics due to strong stray fields generated by ferromagnetic materials like FeCoB, which deteriorate the resistance switching performance.
Innovation Solution
Incorporating non-magnetic materials such as molybdenum (Mo) into the second magnetic layer of a Magnetic Tunnel Junction (MTJ) structure, with a concentration less than 10% and a thickness between 10 Å and 30 Å, to reduce the stray field and improve switching characteristics while maintaining required Tunneling Magneto-Resistance (TMR) values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ferromagnetic materials like FeCoB are used in the second magnetic layer, then the pinned magnetization direction is stable, but strong stray fields are generated that deteriorate resistance switching performance
Solution Approach 1:
The patent changes the chemical composition parameters of the second magnetic layer by adding non-magnetic materials (Ru, Rh, Ir, Mo, Nb, Ta, or W) at controlled concentrations (5-20 at%) to the ferromagnetic material (FeCoB). This parameter modification reduces the magnetization strength and stray field generation while maintaining the pinned magnetization direction stability through the underlying antiferromagnetic layer.
Solution Approach 2:
The patent creates a composite magnetic layer structure by combining ferromagnetic materials (FeCoB) with non-magnetic materials (Ru, Rh, Ir, Mo, Nb, Ta, or W) in specific proportions. This composite structure reduces the overall magnetization and stray field strength while preserving the pinned magnetization function, thereby resolving the contradiction between stability and harmful stray field generation.
2Object-generated harmful factors
If the concentration of non-magnetic material in the second magnetic layer is increased to reduce stray field, then switching characteristics improve, but TMR values may deteriorate
Solution Approach 1:
The patent optimizes the concentration parameter of non-magnetic materials to fall within the specific range of 5-20 at%. This parameter optimization achieves a balance where the stray field is sufficiently reduced to improve switching characteristics, while the TMR value remains above 100% by preventing excessive dilution of the ferromagnetic component that would degrade spin polarization.
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
The introduction of non-magnetic materials like Mo in the second magnetic layer reduces the stray field, enhances switching characteristics, and maintains the necessary TMR values, leading to improved data storage performance in memory devices.
Implementation Method 1
required Tunneling Magneto-Resistance (TMR) values
Implementation Method 2
strong stray fields generated by ferromagnetic materials like FeCoB
Data Source
AI summary
An electronic device includes a semiconductor memory, and the semiconductor memory includes a first magnetic layer having a variable magnetization direction; a second magnetic layer having a pinned magnetization direction; and a tunnel barrier layer interposed between the first magnetic layer and the second magnetic layer, wherein the second magnetic layer includes a ferromagnetic material with molybdenum (Mo) added thereto.