Ferroelectric Memory Stack With Interface Layers for Data Retention

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Solution Overview

Problem

Existing ferroelectric memory devices face challenges in maintaining retention characteristics due to dopant diffusion, which degrades the remanent polarization and reduces data storage reliability.

Innovation Solution

The ferroelectric memory device incorporates a data storage layer with alternating ferroelectric layers and interface layers to prevent dopant diffusion, enhancing retention characteristics by forming trap layers that maintain electrical polarization even without an external electric field.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single ferroelectric layer is used as the data storage layer, then the device structure is simple, but dopant diffusion degrades remanent polarization and reduces data storage reliability

Engineering Contradiction:

Improvedata storage reliabilityVSAvoiddata storage layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The data storage layer is segmented into multiple ferroelectric layers (first, second, and third ferroelectric layers) with different functions. The first and second ferroelectric layers form trap layers for dopant accumulation, while the third ferroelectric layer maintains data storage functionality. This segmentation prevents dopant diffusion from degrading the main storage layer while preserving data reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Interface layers are introduced as intermediary structures between adjacent ferroelectric layers. These interface layers control dopant diffusion and accumulation, allowing dopants to be trapped in specific regions (first and second ferroelectric layers) while protecting the third ferroelectric layer from dopant degradation, thus maintaining both reliability and controlled complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If interface layers are added between ferroelectric layers, then dopant diffusion is prevented and retention characteristics improve, but manufacturing complexity increases

Engineering Contradiction:

Improveretention characteristicsVSAvoidfabrication process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The interface layers are formed between ferroelectric layers during the deposition process, establishing dopant diffusion barriers before dopant introduction occurs. This preliminary structural preparation ensures that when dopants are subsequently introduced, they are automatically confined to specific regions, improving retention characteristics while using standard sequential deposition techniques.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If multiple ferroelectric layers are stacked to prevent dopant diffusion, then polarization levels are maintained, but device fabrication complexity increases

Engineering Contradiction:

Improvepolarization level controlVSAvoidlayer stack structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Different ferroelectric layers are assigned different local qualities and functions: the first and second ferroelectric layers are designed for dopant trapping with appropriate thickness and material properties, while the third ferroelectric layer is optimized for data storage with enhanced polarization stability. This local differentiation allows precise control of polarization levels in the storage layer without requiring all layers to have identical complex structures.

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

The solution effectively mitigates dopant diffusion, improving the retention characteristics and data storage reliability by maintaining polarization levels, thus ensuring stable data retention.

Implementation Method 1

A ferroelectric memory device including ferroelectric random access memory may use spontaneous polarization characteristics of ferroelectric material to store data

Methodology Applied

Scientific EffectSpontaneous polarization: Polarisation

Implementation Method 2

The ferroelectric memory device incorporates a data storage layer with alternating ferroelectric layers and interface layers to prevent dopant diffusion

Methodology Applied

Scientific EffectDopant diffusion prevention: Diffusion Barrier

Data Source

PatentUS12581658B2Ferroelectric memory with multiple ferroelectric layers through a stack of gate lines

Publication Date: 2026.03.17 SK HYNIX INC

AI summary

A ferroelectric memory device includes interlayer insulating layers and gate lines alternately stacked, a data storage layer vertically passing through the interlayer insulating layers and the gate lines and having a cylindrical shape, and a channel layer formed in an area enclosed by the data storage layer. The data storage layer includes a first ferroelectric layer abutting on the channel layer, a second ferroelectric layer abutting on the interlayer insulating layers and the gate lines, and an interface layer formed between the first and the second ferroelectric layers.