Oxygen-Free Dielectric Interface Layer for TFT Metal Electrodes

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Solution Overview

Problem

In thin film transistor (TFT) device manufacturing, the interface between metal electrode layers and insulating materials often results in impurity diffusion, leading to poor electrical performance and short device lifespan due to improper material selection, causing current shorts and leakage.

Innovation Solution

A method involving the formation of an oxygen-free dielectric interface layer, typically a silicon nitride layer, between the metal electrode layer and the insulating layer to prevent element diffusion, enhancing interface management and electrical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If an insulating material layer is directly formed on a metal electrode layer, then the device structure is simpler, but impurity diffusion occurs leading to poor electrical performance and short device lifespan

Engineering Contradiction:

Improvedevice structureVSAvoidelectrical performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

An oxygen-free dielectric interface layer is introduced between the metal electrode layer and the insulating material layer to prevent direct contact and impurity diffusion. This intermediary layer blocks oxygen penetration and element diffusion, thereby improving electrical performance and device reliability without significantly complicating the overall structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If an oxygen-free dielectric interface layer is added between metal electrode layer and insulating layer, then impurity diffusion is prevented improving electrical performance, but device structure becomes more complex

Engineering Contradiction:

Improveelectrical performanceVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The interface region between the metal electrode layer and insulating material layer is segmented into two distinct layers: an oxygen-free dielectric interface layer and an insulating material layer. This segmentation allows each layer to perform its specific function optimally - the interface layer prevents impurity diffusion while the insulating layer provides electrical insulation.

Inventive Principle:

Principle #1Segmentation

3Stability of the object's composition

If proper interface management is implemented with oxygen-free dielectric layer, then device stability is improved, but manufacturing process becomes more complex

Engineering Contradiction:

Improvedevice stabilityVSAvoidmanufacturing process

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The manufacturing process incorporates specific parameter control during the formation of the oxygen-free dielectric interface layer, including controlling the deposition conditions and material composition to ensure the layer is substantially free of oxygen. This parameter control enables reliable prevention of impurity diffusion while maintaining manufacturability.

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 solution effectively prevents contamination and improves the electrical performance and stability of TFT devices by blocking oxygen penetration and reducing the likelihood of device failure, thereby extending the device's lifespan and enhancing overall performance.

Implementation Method 1

an interface layer disposed on the metal electrode layer, wherein the interface layer is an oxygen free dielectric material layer sized to be formed predominately on the metal electrode layer

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS10170569B2Thin film transistor fabrication utlizing an interface layer on a metal electrode layer

Publication Date: 2019.01.01 APPLIED MATERIALS INC

AI summary

Embodiments of the disclosure generally provide methods of forming thin film transistor (TFT) device structure with good interface management between a metal electrode layer and a nearby insulating material so as to provide high electrical performance devices, or for other suitable display applications. In one embodiment, a thin film transistor structure includes a metal electrode layer disposed on a barrier layer formed above a gate insulating material layer, an interface layer disposed on the metal electrode layer, wherein the interface layer is an oxygen free dielectric material layer sized to be formed predominately on the metal electrode layer, and an insulating material layer disposed on the interface layer, wherein the insulating material layer is an oxygen containing dielectric layer.