Magnetically Doped SOT Electrode for MRAM Switching

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Solution Overview

Problem

Legacy MRAM technologies face complexity in fabrication and reliability due to the need for antiferromagnetic materials and complex circuits for in-plane spin orbit torque switching, which limits tunnel magnetoresistance yield and Neel temperature.

Innovation Solution

Incorporating magnetic material into the SOT electrode to create a doped SOT electrode with in-plane magnetic anisotropy, allowing for direct spin orbit coupling and simplifying the MRAM stack, enabling deterministic bidirectional switching of the perpendicular magnetic polarity in the MTJ free layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If antiferromagnetic materials and complex circuits are used for in-plane spin orbit torque switching, then switching functionality is achieved, but fabrication complexity increases and reliability decreases

Engineering Contradiction:

ImproveMRAM reliabilityVSAvoidfabrication complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the SOT electrode and magnetic field generation functions into a single magnetically doped SOT electrode layer. This integration eliminates the need for separate antiferromagnetic material layers and complex circuit configurations, thereby reducing fabrication complexity while maintaining switching functionality and improving reliability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The magnetically doped SOT electrode serves multiple functions: it generates spin-orbit torque for switching and simultaneously provides the magnetic field necessary for perpendicular magnetic anisotropy. This multi-functionality eliminates the need for additional dedicated components, simplifying the overall device structure and fabrication process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If additional magnetic inserts or vias are added to enhance magnetic field, then switching performance improves, but device complexity and fabrication steps increase

Engineering Contradiction:

ImproveTMR yieldVSAvoidfabrication ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the magnetic field enhancement function directly into the SOT electrode through magnetic doping. This eliminates the need for additional magnetic inserts or vias that would otherwise be required to provide the necessary magnetic field, thereby maintaining TMR yield while simplifying fabrication.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The SOT electrode is created as a composite material by doping it with magnetic materials. This composite structure inherently provides both the spin-orbit coupling necessary for SOT switching and the magnetic field required for perpendicular magnetic anisotropy, eliminating the need for separate magnetic components.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If magnetic material is incorporated into SOT electrode, then effective magnetic field is enhanced and switching is simplified, but material composition complexity increases

Engineering Contradiction:

Improvefabrication simplicityVSAvoidmaterial composition complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the magnetic material into the SOT electrode layer through doping, creating a single integrated layer that provides both spin-orbit coupling and magnetic field generation. This approach simplifies fabrication by reducing the number of discrete layers and interfaces, despite the increased complexity of the material composition itself.

Inventive Principle:

Principle #5Merging (Combining)

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 simplifies the fabrication process, enhances the effective magnetic field on the MTJ free layer, and achieves repeatable bidirectional switching without the need for additional magnetic inserts or vias, improving the reliability and TMR yield of MRAM.

Implementation Method 1

electron spin currents arising from the spin-Hall effect (SHE) within heavy metals has been shown to apply spin-transfer torques to a magnet

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 2

electron spin currents arising from the spin-Hall effect (SHE) within heavy metals has been shown to apply spin-transfer torques to a magnet

Methodology Applied

Scientific EffectSpin-Hall effect:

Implementation Method 3

This moment may interact with the adjacent MTJ free layer due to a dipole interaction, and may apply an effective field on the free layer magnet in a direction opposite to the internal magnetic moment

Methodology Applied

Scientific EffectDipole interaction:

Data Source

PatentUS11417830B2Magnetically doped spin orbit torque electrode for perpendicular magnetic random access memory

Publication Date: 2022.08.16 INTEL CORP

AI summary

Embodiments herein relate to magnetically doping a spin orbit torque electrode (SOT) in a magnetic random access memory apparatus. In particular, the apparatus may include a free layer of a magnetic tunnel junction (MTJ) coupled to a SOT electrode that is magnetically doped to apply an effective magnetic field on the free layer, where the free layer has a magnetic polarization in a first direction and where current flowing through the magnetically doped SOT electrode is to cause the magnetic polarization of the free layer to change to a second direction that is substantially opposite to the first direction.