Skyrmionic Enhancement Layer for MRAM Switching Speed

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Solution Overview

Problem

Conventional MRAM devices face challenges in reducing incubation periods, which dominate the switching time, and require high switching currents, affecting their performance and endurance.

Innovation Solution

The introduction of a skyrmionic enhancement layer with a Dzyaloshinskii-Moriya interaction (DMI) near the free layer and precessional spin current layer, utilizing non-magnetic heavy metals with large spin-orbit coupling, such as tungsten, iridium, and platinum, to facilitate local canting of atomic spins and enhance the effectiveness of spin-polarized switching currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional MRAM devices use standard switching mechanisms, then the device structure remains simple, but the incubation period is long and switching speed is slow

Engineering Contradiction:

Improveswitching speedVSAvoiddevice structure

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent segments the magnetic layer into multiple functional components: a free layer with perpendicular magnetic anisotropy and a precessional spin current layer with in-plane magnetization. This segmentation allows independent optimization of switching dynamics and reduces incubation period while maintaining overall device functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a precessional spin current layer as an intermediary between the spin-polarized current and the free layer. This intermediary layer converts the applied current into precessional motion that efficiently switches the free layer magnetization, thereby reducing switching current and improving speed without excessive structural complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If high switching currents are used to switch the free layer, then switching speed improves, but energy consumption increases and endurance decreases

Engineering Contradiction:

Improveswitching speedVSAvoidswitching current

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent employs dynamic precessional motion of the spin current layer magnetization to switch the free layer. By utilizing the dynamic precessional response rather than direct static switching, the system achieves efficient magnetization reversal at lower current densities, reducing energy consumption while maintaining high switching speed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the magnetization orientation parameter of the spin current layer from perpendicular to in-plane, creating a precessional mode that is more responsive to spin-polarized currents. This parameter change enables lower switching currents by exploiting the dynamic precessional response of the magnetic layer.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If the incubation period is reduced to improve switching time, then switching speed increases, but the device requires more complex structures to initiate switching

Engineering Contradiction:

Improveincubation periodVSAvoidlayer structure

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies a magnetic field or spin-polarized current to the spin current layer before the main switching current is applied. This preliminary action precesses the magnetization of the spin current layer into a configuration that is more responsive to the subsequent switching current, thereby reducing the incubation period without requiring overly complex structural modifications.

Inventive Principle:

Principle #10Preliminary action

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 reduces incubation periods, increases switching speed, and lowers the required switching current, thereby improving the overall performance and endurance of MRAM devices by promoting efficient spin torques and overcoming pinning effects due to material imperfections.

Implementation Method 1

a skyrmionic enhancement layer disposed over the precessional spin current layer and formed from a heavy metal with large spin-orbit coupling, such that the skyrmionic enhancement layer induces a Dzyaloshinskii-Moriya interaction at an interface between the precessional spin current layer and the skyrmionic enhancement layer thereby creating local canting of the atomic spins

Methodology Applied

Scientific EffectDzyaloshinskii-Moriya interaction:

Implementation Method 2

formed from a heavy metal with large spin-orbit coupling, such as tungsten, iridium, and platinum, to facilitate local canting of atomic spins

Methodology Applied

Scientific EffectSpin-orbit coupling:

Implementation Method 3

enhance the effectiveness of spin-polarized switching currents... promoting efficient spin torques

Methodology Applied

Scientific EffectSpin transfer torque:

Data Source

PatentUS10468588B2Perpendicular magnetic tunnel junction device with skyrmionic enhancement layers for the precessional spin current magnetic layer

Publication Date: 2019.11.05 INTEGRATED SILICON SOLUTION CAYMAN INC

AI summary

A magnetoresistive random-access memory (MRAM) is disclosed. The MRAM device includes a perpendicular magnetic tunnel junction device having a reference layer, a free layer, and a precessional spin current magnetic layer. A skyrmionic enhancement layer is provided adjacent to the precessional spin current magnetic layer. The skyrmionic enhancement layer helps to improve the response of the precessional spin current magnetic layer to applied spin polarized currents.