Multi-Layer Ferroelectric Memory Electrodes to Prevent Oxide Formation

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Solution Overview

Problem

Ferroelectric random-access memory (FeRAM) devices face issues with oxide formation between electrodes and the ferroelectric switching layer during high-temperature baking processes, leading to defects that impair data storage capabilities.

Innovation Solution

Implementing a multi-layer electrode structure with a second electrode layer having a higher corrosion potential than the first electrode layer, positioned between the first electrode layer and the ferroelectric switching layer, to mitigate oxide formation and reduce oxygen vacancies, thereby enhancing the switching performance and endurance of the memory device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-layer electrode structure is used, then the device complexity is low, but oxide formation occurs between the electrode and ferroelectric switching layer during high-temperature baking

Engineering Contradiction:

Improveoxide formation preventionVSAvoidelectrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electrode is divided into multiple layers with different corrosion potentials. The first electrode layer has a first corrosion potential and the second electrode layer has a second corrosion potential that is higher than the first corrosion potential. This segmentation allows each layer to perform a specific function in preventing oxide formation during high-temperature baking processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The multi-layer electrode structure combines materials with different corrosion potentials to create a composite electrode system. This composite structure leverages the electrochemical properties of each material layer to collectively prevent oxide formation at the interface with the ferroelectric switching layer, resolving the contradiction between reliability and complexity.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If high-temperature baking is performed to improve manufacturing precision, then defects are reduced, but oxide formation occurs between electrodes and ferroelectric switching layer

Engineering Contradiction:

Improvedefect reductionVSAvoidoxide formation

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The multi-layer electrode structure is designed in advance to counteract the harmful effect of oxide formation that occurs during high-temperature baking. The second electrode layer with higher corrosion potential acts as a protective barrier that prevents oxygen from reaching the first electrode layer and forming oxides, allowing high-temperature processing to be performed without the harmful side effect of oxide formation.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The second electrode layer serves as an intermediary between the first electrode layer and the oxygen environment during high-temperature baking. This intermediate layer with higher corrosion potential blocks the direct interaction between oxygen and the first electrode layer, preventing oxide formation while allowing the beneficial high-temperature processing to occur.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the second electrode layer with higher corrosion potential is added, then oxide formation is mitigated, but the device complexity increases

Engineering Contradiction:

Improveswitching performanceVSAvoidelectrode layers

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the corrosion potential parameter of the electrode layers by introducing a second layer with a higher corrosion potential than the first layer. This parameter change enables the electrode structure to resist oxide formation during high-temperature processing, improving reliability despite the increased structural complexity.

Inventive Principle:

Principle #35Parameter changes

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 multi-layer electrode configuration effectively prevents oxide formation and defects, ensuring the intrinsic electric dipole can switch between polarization states efficiently, improving the memory device's performance and data retention at high temperatures.

Implementation Method 1

the second electrode layer has a second corrosion potential that is higher than the first corrosion potential, and the second electrode layer is configured to mitigate formation of an oxide between the multi-layer top or bottom electrodes and the ferroelectric switching layer

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11916127B2Multi-layer electrode to improve performance of ferroelectric memory device

Publication Date: 2024.02.27 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Various embodiments of the present disclosure are directed towards a memory device including a first bottom electrode layer over a substrate. A ferroelectric switching layer is disposed over the first bottom electrode layer. A first top electrode layer is disposed over the ferroelectric switching layer. A second bottom electrode layer is disposed between the first bottom electrode layer and the ferroelectric switching layer. The second bottom electrode layer is less susceptible to oxidation than the first bottom electrode layer.