Doped Antiferromagnetic SOT Electrode for Fast Switching

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Spintronic memory technologies, such as STT-MRAM, face challenges with high voltage and current requirements during programming, leading to reliability issues and slow switching times due to large write currents and low blocking temperatures of antiferromagnetic materials used in SOT electrodes.

Innovation Solution

The use of doped or co-sputtered antiferromagnetic materials with high blocking temperatures, such as IrMn doped with Pt, Ni, or Cr, and the incorporation of multilayer AFM structures with heavy metals, oxygen, or nitrogen, to enhance spin orbit torque and maintain thermal stability, allowing for lower write currents and faster switching times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If large write current is used to write a tunnel junction based magnetic tunnel junction (MTJ), then the writing speed is improved, but reliability deteriorates due to reliability issues in magnetic tunnel junctions caused by large current flowing through tunnel barrier

Engineering Contradiction:

Improvewriting speedVSAvoidreliability of magnetic tunnel junctions

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent introduces a spin orbit coupling interconnect as an intermediary component between the current source and the MTJ. This interconnect converts charge current to spin current through the spin Hall effect, allowing the MTJ to be written with lower charge current while maintaining fast switching speeds. The spin current acts as a mediator that transfers angular momentum to the magnetization without requiring large current through the tunnel barrier.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the direct electrical current mechanism (charge current through tunnel barrier) with a spin-mediated mechanism (spin current through spin orbit coupling). This substitution changes the fundamental writing mechanism from direct charge transport to spin angular momentum transfer, enabling faster and more reliable writing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If antiferromagnetic materials with low blocking temperature are used in SOT electrodes, then spin orbit torque is enhanced, but thermal stability deteriorates

Engineering Contradiction:

Improvespin orbit torque efficiencyVSAvoidblocking temperature

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The patent uses composite antiferromagnetic materials such as IrMn doped with Pt, Ni, or Cr, and multilayer AFM structures with heavy metals, oxygen, or nitrogen. These composite materials combine the high spin orbit torque efficiency of traditional AFM materials with enhanced blocking temperatures, achieving both high power efficiency and thermal stability simultaneously.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the material composition parameters of the antiferromagnetic layer by introducing dopants (Pt, Ni, Cr) and forming multilayer structures. These parameter changes increase the blocking temperature while maintaining or enhancing the spin Hall angle, thus improving both thermal stability and spin orbit torque efficiency.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If doped or co-sputtered antiferromagnetic materials with high blocking temperatures are used, then thermal stability is improved, but device complexity increases due to doping processes

Engineering Contradiction:

Improveblocking temperatureVSAvoidcomplexity of doping processes

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent incorporates dopants (Pt, Ni, Cr) and other materials during the initial deposition process using co-sputtering or doping techniques. By performing the doping action preliminarily during fabrication rather than requiring subsequent processing steps, the blocking temperature is enhanced without significantly increasing overall device complexity or process complexity.

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 write error rates, achieves faster switching times (less than 10 ns), and improves the reliability of magnetic tunnel junctions by enabling lower write currents and higher temperature operation without compromising the antiferromagnetic nature, thus enhancing the overall performance of perpendicular spin orbit torque MRAM.

Implementation Method 1

spin orbit torque (SOT) based magnetic memory in which a spin orbit coupling (SOC) interconnect is used to switch a magnetization of a magnetic junction

Methodology Applied

Scientific EffectSpin Hall Effect: Hall Effect

Data Source

PatentUS11251365B2High blocking temperature spin orbit torque electrode

Publication Date: 2022.02.15 INTEL CORP

AI summary

An apparatus is provided which comprises: a magnetic junction having a magnet with a first magnetization; an interconnect adjacent to the magnetic junction, wherein the interconnect comprises an antiferromagnetic (AFM) material which is doped with a doping material (Pt, Ni, Co, or Cr) and a structure adjacent to the interconnect such that the magnetic junction and the structure are on opposite surfaces of the interconnect, wherein the structure comprises a magnet with a second magnetization substantially different from the first magnetization.