Magnetic Junction Insertion Layer for Thermal Stability

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Solution Overview

Problem

Conventional magnetic junctions in spin transfer torque random access memories (STT-MRAMs) face challenges in maintaining low switching current, thermal stability, and high perpendicular magnetic anisotropy, which are crucial for efficient write operations and data retention, especially under high temperature anneals.

Innovation Solution

The magnetic device incorporates a pinned layer, a perpendicular enhancement layer (PEL), an insertion layer with high crystallization temperature nonmagnetic materials like Hf, and a free layer, along with a nonmagnetic spacer layer, to enhance perpendicular magnetic anisotropy and stability, utilizing spin-orbit interaction torque for switching between stable magnetic states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional magnetic junctions are used in STT-MRAMs, then the device structure is simple, but the thermal stability and perpendicular magnetic anisotropy are insufficient under high temperature anneals

Engineering Contradiction:

Improvethermal stabilityVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The magnetic junction is segmented into multiple functional layers including a pinned layer, perpendicular enhancement layer, insertion layer with high crystallization temperature materials, and free layer. This segmentation allows each layer to contribute specific properties that collectively enhance thermal stability and perpendicular magnetic anisotropy while maintaining overall device functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The insertion layer combines magnetic materials with high crystallization temperature nonmagnetic materials to create a composite structure. This composite material approach enables the junction to maintain low switching current while achieving high thermal stability and perpendicular magnetic anisotropy that withstands high temperature anneals.

Inventive Principle:

Principle #40Composite materials

2Reliability

If high perpendicular magnetic anisotropy is achieved through material composition, then thermal stability improves, but switching current increases

Engineering Contradiction:

Improveperpendicular magnetic anisotropyVSAvoidswitching current

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes parameters such as layer thickness, material composition ratios, and crystallization temperature to achieve the desired balance. By carefully controlling these parameters, the junction achieves high perpendicular magnetic anisotropy while maintaining low switching current through precise structural design.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Different regions of the magnetic junction are designed with locally optimized properties. The insertion layer with high crystallization temperature materials provides localized thermal stability, while the perpendicular enhancement layer and free layer are configured to maintain low switching current. This local quality approach allows simultaneous optimization of both thermal stability and switching efficiency.

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 improves resistance to degradation after high temperature anneals, maintaining desired exchange fields and reducing write error rates, thereby enhancing the performance and stability of magnetic junctions in STT-MRAMs.

Implementation Method 1

The at least one SO active layer is adjacent to the free layer of the magnetic junction. The SO active layer(s) carry a current in-plane and exert a SO torque on the free layer due to the current passing through the SO active layer(s). The free layer is switchable between stable magnetic states using the SO torque

Methodology Applied

Scientific EffectSpin-orbit interaction torque:

Implementation Method 2

The insertion layer includes at least one magnetic material and at least one high crystallization temperature nonmagnetic material such as Hf

Methodology Applied

Scientific EffectHigh crystallization temperature:

Implementation Method 3

The PEL and free and pinned layers each has a perpendicular magnetic anisotropy energy greater than its out-of-plane demagnetization energy

Methodology Applied

Scientific EffectPerpendicular magnetic anisotropy: Anisotropy

Data Source

PatentUS10297301B2Method and system for providing magnetic junctions utilizing high crystallization temperature-containing insertion layer(s)

Publication Date: 2019.05.21 SAMSUNG ELECTRONICS CO LTD

AI summary

A magnetic device and method for providing the magnetic device junction are described. The magnetic device includes magnetic junctions and spin-orbit interaction (SO) active layer(s). The magnetic junction includes a pinned layer, a perpendicular enhancement layer (PEL), an insertion layer between the pinned layer and PEL, a free layer and a nonmagnetic spacer layer between the PEL and free layer. The insertion layer includes at least one magnetic material and at least one high crystallization temperature nonmagnetic material. The PEL is between the insertion layer and the nonmagnetic spacer layer. The free layer is switchable between a plurality of stable magnetic states. The PEL and free and pinned layers each has a perpendicular magnetic anisotropy energy greater than its out-of-plane demagnetization energy. The SO active layer(s) are adjacent to the free layer, carry a current in-plane and exert a SO torque on the free layer due to the current.