Discontinuous Free Layer Gap Structure for SOT MRAM Fabrication

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Solution Overview

Problem

The manufacturing of spin-orbit-torque magnetic random access memory (SOT MRAM) is complicated and costly due to the requirement of external or internal magnetic fields, which complicates the fabrication process and increases costs.

Innovation Solution

A method for fabricating magnetic tunnel junction (MTJ) structures with a gap surrounding the MTJ pillar structure, allowing an intrinsic magnetic field to be generated by a discontinuous free layer, eliminating the need for external magnetic field generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external or internal magnetic field generation is used in SOT MRAM, then the magnetic tunnel junction can be operated, but the manufacturing process becomes complicated and costs increase

Engineering Contradiction:

Improvedevice operationVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the external magnetic field generation components from the SOT MRAM device. By forming a gap structure that eliminates the need for separate magnetic field generation layers, the invention simplifies the manufacturing process while maintaining device operation capability through the intrinsic magnetic field generated by the discontinuous free layer

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the magnetic field generation function into the free layer structure itself. The discontinuous free layer configuration enables the layer to generate its own magnetic field, combining the storage and field generation functions into a single integrated structure, thereby eliminating separate magnetic field generation components

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If external or internal magnetic field generation is used in SOT MRAM, then the magnetic tunnel junction can be operated, but manufacturing costs increase

Engineering Contradiction:

Improvedevice operationVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a simple gap structure formed by selective removal of material rather than expensive permanent magnetic field generation components. The discontinuous free layer configuration provides a low-cost solution that generates the necessary magnetic field intrinsically, eliminating the need for additional expensive magnetic field generation layers

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 manufacturing process, reduces costs, and maintains or enhances device performance by eliminating the need for external magnetic field generation and reducing manufacturing complexity.

Implementation Method 1

allowing an intrinsic magnetic field to be generated by a discontinuous free layer

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS10497858B1Methods for forming structures for MRAM applications

Publication Date: 2019.12.03 APPLIED MATERIALS INC

AI summary

Embodiments of the disclosure provide methods and apparatus for fabricating magnetic tunnel junction (MTJ) structures on a substrate for MRAM applications, particularly for spin-orbit-torque magnetic random access memory (SOT MRAM) applications. In one embodiment, a magnetic tunnel junction (MTJ) device structure includes a magnetic tunnel junction (MTJ) pillar structure disposed on a substrate, and a gap surrounding the MTJ pillar structure. In yet another embodiment, a magnetic tunnel junction (MTJ) device structure includes a spacer layer surrounding a patterned reference layer and a tunneling barrier layer disposed on a patterned free layer, and a gap surrounding the patterned free layer.