Magnetic Device Blocking Layer for High-Temperature PMA Stability

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Solution Overview

Problem

Current magnetic devices with perpendicular magnetic anisotropy (PMA) face challenges in maintaining stability at high temperatures and achieving low-current operation while maintaining a high tunneling magnetoresistance ratio (TMR).

Innovation Solution

The magnetic device incorporates a free layer, a pinned layer, a tunnel barrier, a polarization enhancement layer, and a blocking layer with a first and second diffusion trap layer, which includes transition metals, to enhance magnetic coupling and prevent diffusion of materials, thereby maintaining PMA and TMR at high temperatures and enabling low-current operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a magnetic tunnel junction (MTJ) cell is finely sized for high integration, then device density is improved, but perpendicular magnetic anisotropy (PMA) stability deteriorates at high temperatures

Engineering Contradiction:

Improvedevice densityVSAvoidPMA stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A blocking layer comprising a transition metal layer and a magnetic layer is introduced as an intermediary between the pinned layer and the tunnel barrier. This blocking layer acts as a mediator to provide thermal stability and maintain perpendicular magnetic anisotropy at high temperatures, resolving the contradiction between high device density and PMA stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The blocking layer is constructed as a composite structure with a transition metal layer (e.g., Pt, Pd, Ir) and a magnetic layer (e.g., CoFeB, CoFe). This composite material configuration provides both the necessary magnetic properties for spin transfer torque and thermal stability for maintaining PMA at high temperatures, while allowing for finely sized MTJ cells.

Inventive Principle:

Principle #40Composite materials

2Speed

If current is directly applied to the MTJ cell for STT-MRAM operation, then switching speed is improved, but current consumption increases

Engineering Contradiction:

Improveswitching speedVSAvoidcurrent consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The blocking layer modifies the magnetic parameters of the MTJ structure by providing enhanced perpendicular magnetic anisotropy and reduced damping. This allows for lower critical current densities to achieve magnetization switching, thereby reducing current consumption while maintaining fast switching speeds characteristic of STT-MRAM operation.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the MTJ structure is optimized for low-current operation, then energy efficiency is improved, but tunneling magnetoresistance ratio (TMR) decreases

Engineering Contradiction:

Improvecurrent consumptionVSAvoidTMR ratio

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The blocking layer is strategically positioned between the pinned layer and tunnel barrier, creating localized quality enhancement at the critical interface. This local optimization provides both low-current operation capability through enhanced PMA and maintains high TMR ratio by preserving the spin polarization at the tunnel barrier interface, resolving the contradiction between energy efficiency and measurement precision.

Inventive Principle:

Principle #3Local quality

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 ensures stable perpendicular magnetic anisotropy at high temperatures and supports low-current read and write operations while securing a high tunneling magnetoresistance ratio, enhancing the performance of magnetic memory devices.

Implementation Method 1

a blocking layer disposed between the polarization enhancement layer and the pinned layer, wherein the blocking layer may include a first diffusion trap layer and a second diffusion trap layer disposed on the first diffusion trap layer

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

a spin transfer torque (STT)-MRAM has been spotlighted because current is directly applied to the MTJ cell, which induces a magnetization inversion and stores information by a physical phenomenon of STT

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 3

Much research has been conducted into electronic devices that use a magnetic resistance property of a magnetic tunnel junction (MTJ)

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Data Source

PatentUS10249817B2Magnetic device

Publication Date: 2019.04.02 SAMSUNG ELECTRONICS CO LTD

AI summary

A magnetic device includes a free layer; a pinned layer; a tunnel barrier disposed between the free layer and the pinned layer; a polarization enhancement layer disposed between the tunnel barrier and the pinned layer; and a blocking layer disposed between the polarization enhancement layer and the pinned layer, wherein the blocking layer includes a first diffusion trap layer and a second diffusion trap layer disposed on the first diffusion trap layer.