Oxide Semiconductor TFT Hydrogen Blocking Layer
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Solution Overview
Problem
Thin film transistors using oxide semiconductors face deterioration of electrical characteristics due to hydrogen exposure during the passivation process, which affects charge mobility and long-term reliability.
Innovation Solution
Incorporating a hydrogen blocking layer, such as aluminum-neodymium oxide or aluminum-nickel-lanthanum oxide, between the active layer and the passivation layer to prevent hydrogen diffusion, thereby stabilizing the electrical characteristics and maintaining charge concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passivation layer is formed using CVD or PECVD to protect the thin film transistor, then the device is protected from environmental degradation, but hydrogen from the deposition gas flows through the active layer causing deterioration of electrical characteristics and long-term reliability
Solution Approach 1:
The patent introduces a hydrogen blocking layer as an intermediary between the active layer and the passivation layer. This blocking layer specifically prevents hydrogen from the passivation deposition process from reaching the active layer, while allowing the passivation layer to still provide its protective function. The blocking layer acts as a mediator that selectively blocks harmful hydrogen transport.
Solution Approach 2:
The patent segments the protective structure into multiple functional layers: the passivation layer for environmental protection, the hydrogen blocking layer for selective hydrogen prevention, and the etching stopping layer for process control. This segmentation allows each layer to perform its specific function independently, solving the contradiction between protection and hydrogen exposure.
2Manufacturing precision
If gas containing hydrogen (such as SiH4 and NH3) is used during passivation layer deposition, then the passivation layer can be effectively formed, but the hydrogen flows through the active layer causing initial characteristic deterioration
Solution Approach 1:
The hydrogen blocking layer serves as an intermediary that allows the passivation layer deposition process to proceed normally using hydrogen-containing gases, while simultaneously preventing the hydrogen from reaching the active layer. This resolves the contradiction by decoupling the deposition process from its harmful byproduct.
Solution Approach 2:
The patent applies local quality by making different layers have different permeability properties. The hydrogen blocking layer has low hydrogen permeability specifically at the interface with the active layer, while the passivation layer maintains its deposition characteristics. This localized property differentiation solves the contradiction between effective passivation formation and hydrogen prevention.
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 hydrogen blocking layer effectively suppresses the deterioration of the active layer's characteristics, reducing initial threshold voltage changes and enhancing the long-term reliability of the thin film transistor.
Implementation Method 1
a hydrogen blocking layer which blocks hydrogen diffused from the passivation layer, thereby suppressing characteristic deterioration of the active layer
Data Source
AI summary
In an aspect, a display device including: a substrate; a thin film transistor formed on the substrate, and comprising an active layer formed of an oxide semiconductor; a passivation layer formed on the thin film transistor; and a hydrogen blocking layer positioned between the active layer and the passivation layer is provided.