Perpendicular STTM Free Layer Interleaved Insert Layers

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Perpendicular spin transfer torque memory (pSTTM) devices face challenges in reducing damping while maintaining stability, which affects the switching current and data retention time due to the use of non-magnetic insert layers in the free magnetic stack.

Innovation Solution

Interleaving multiple non-magnetic insert layers between magnetic layers within the free magnetic stack enhances interfacial anisotropy and reduces damping, thereby improving stability and reducing the switching current required for data storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If non-magnetic insert layers are used in the free magnetic stack, then stability is improved, but damping increases which worsens switching current

Engineering Contradiction:

Improvedata stabilityVSAvoiddamping

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The free magnetic stack is segmented into multiple magnetic layers separated by non-magnetic insert layers. This segmentation creates multiple interfaces that collectively enhance interfacial anisotropy while distributing the damping effect, allowing the system to achieve both stability and low switching current

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The free magnetic stack uses a composite structure combining magnetic layers (providing magnetization) with non-magnetic insert layers (providing interface anisotropy). This composite approach allows the system to benefit from both the magnetic properties and the interfacial effects, resolving the contradiction between stability and damping

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If non-magnetic insert layers are used in the free magnetic stack, then data retention time is improved, but switching current increases

Engineering Contradiction:

Improvedata retention timeVSAvoidswitching current

Core Design Contradiction:

Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

The invention optimizes parameters including the thickness of non-magnetic insert layers (0.2-2.0 nm), the number of magnetic layers (2-5 layers), and the total thickness of the free magnetic stack (3-10 nm). These parameter changes enable the system to achieve high data retention while reducing switching current through enhanced interfacial anisotropy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention transitions from a single-layer magnetic structure to a multi-layered vertical structure, adding the dimension of layering. This dimensional change creates multiple interfaces that collectively enhance interfacial anisotropy, improving both data retention and reducing switching current simultaneously

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 effectively decreases the switching current and increases data stability by enhancing interfacial anisotropy, leading to improved performance in pSTTM devices.

Implementation Method 1

Spin transfer torque (STT) uses a current formed from spin-aligned or polarized electrons to develop a torque that is transferred to the free magnetic element to change the magnetic state of the free magnetic element

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 2

Interleaving multiple non-magnetic insert layers between magnetic layers within the free magnetic stack enhances interfacial anisotropy and reduces damping, thereby improving stability

Methodology Applied

Scientific EffectInterfacial anisotropy: Anisotropy

Implementation Method 3

Methodology Applied

Scientific EffectDamping: Damping

Data Source

PatentUS11295884B2Perpendicular STTM multi-layer insert free layer

Publication Date: 2022.04.05 INTEL CORP

AI summary

A perpendicular spin transfer torque memory (pSTTM) device incorporates a magnetic tunnel junction (MTJ) device having a free magnetic stack that includes a plurality of magnetic layers interleaved with a plurality of non-magnetic insert layers. The layers are arranged such that the topmost and bottommost layers are magnetic layers. The stacked design decreases the damping of the MTJ free magnetic stack, beneficially reducing the write current required to write to the pSTTM device. The stacked design further increases the interface anisotropy, thereby beneficially improving the stability of the pSTTM device. The non-magnetic interface layer may include tantalum, molybdenum, tungsten, hafnium, or iridium, or a binary alloy containing at least two of tantalum, molybdenum, tungsten hafnium, or iridium.