Ferroelectric Memory Device Oxygen Vacancy Alignment

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Solution Overview

Problem

Current methods for fabricating ferroelectric memory devices face challenges in effectively controlling the polarization axes of ferroelectric layers, which affects the reliability of switching characteristics and data storage.

Innovation Solution

A method involving the formation of an oxygen vacancy region in a ferroelectric layer through surface treatment, followed by annealing to crystallize the layer, with the gate electrode layer acting as a capping layer, to align polarization axes perpendicular to the substrate, enhancing remanent polarization and switching reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fabrication methods are used without surface treatment, then the manufacturing process is simpler, but the polarization axes cannot be effectively controlled

Engineering Contradiction:

Improvepolarization axis controlVSAvoidfabrication process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies surface treatment to the ferroelectric layer before forming the gate electrode layer. This preliminary action creates oxygen vacancy regions that serve as nucleation sites for subsequent crystallization, enabling effective polarization axis control during the annealing process without adding excessive complexity to the overall fabrication流程

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the oxygen concentration parameter in the ferroelectric layer by applying surface treatment that creates oxygen vacancy regions. This parameter change (reducing oxygen concentration locally) triggers preferential crystallization and enables control over the polarization axis orientation during the annealing process

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the ferroelectric layer is annealed without surface treatment, then the process is simpler, but the crystallization and polarization alignment are insufficient

Engineering Contradiction:

Improveswitching characteristic reliabilityVSAvoidfabrication ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Surface treatment is performed as a preliminary step before annealing to create oxygen vacancy regions in the ferroelectric layer. These pre-formed vacancy regions act as templates that guide crystallization during annealing, ensuring proper polarization axis alignment and improving switching characteristic reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes the phase transition from amorphous to crystalline state during annealing. By precreating oxygen vacancy regions through surface treatment, the phase transition occurs in a controlled manner with preferential crystallization, leading to aligned polarization axes and improved device reliability

Inventive Principle:

Principle #36Phase transitions

3Reliability

If oxygen vacancies are not increased through surface treatment, then the material structure remains unchanged, but remanent polarization and switching reliability cannot be maximized

Engineering Contradiction:

Improveremanent polarization stabilityVSAvoidprocess steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the oxygen vacancy concentration parameter in the ferroelectric layer by applying surface treatment. This parameter change increases oxygen vacancies locally, which serve as nucleation sites for crystallization and enable control over polarization axis orientation, thereby maximizing remanent polarization and switching reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The surface treatment creates localized oxygen vacancy regions within the ferroelectric layer rather than uniformly distributing vacancies throughout. This local quality change allows controlled nucleation sites to form preferentially, guiding crystallization and polarization alignment in specific regions to enhance overall device performance

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 approach improves the reliability of switching characteristics by stabilizing ferroelectric properties and maximizing the attractive and repulsive forces for electron induction and repulsion, respectively, in ferroelectric memory devices.

Implementation Method 1

applying a surface treatment process to the ferroelectric layer to form an oxygen vacancy region in the ferroelectric layer

Methodology Applied

Scientific EffectOxygen vacancy formation:

Implementation Method 2

annealing the ferroelectric layer to crystallize the ferroelectric layer

Methodology Applied

Scientific EffectAnnealing: Annealing

Implementation Method 3

annealing the ferroelectric layer to crystallize the ferroelectric layer

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentUS10475653B2Methods of fabricating ferroelectric memory devices

Publication Date: 2019.11.12 MIMIRIP LLC

AI summary

A method of fabricating a ferroelectric memory device is provided. The method includes preparing a substrate, forming an interfacial insulation layer on the substrate, forming a ferroelectric layer on the interfacial insulation layer, applying a surface treatment process to the ferroelectric layer to form an oxygen vacancy region in the ferroelectric layer, forming a gate electrode layer on the ferroelectric layer, and annealing the ferroelectric layer to crystallize the ferroelectric layer.