Oxide TFT Passivation Structure to Prevent Hydrogen-Induced Conductorization
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Solution Overview
Problem
In metal oxide thin film transistors (TFTs), excessive hydrogen ions in the passivation layer can diffuse into the oxide semiconductor layer, causing conductorization and short-circuit issues, which affect the performance and stability of TFT devices.
Innovation Solution
A composite passivation layer structure comprising multiple silicon oxide layers and a silicon oxynitride layer is used, where the silicon oxide layers are deposited with varying gas flow ratios and thicknesses to prevent hydrogen diffusion, and the silicon oxynitride layer is annealed at a temperature not exceeding 250°C to reduce hydrogen content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passivation layer is used to protect the oxide semiconductor layer, then device stability is improved, but hydrogen ions in the passivation layer can diffuse into the oxide semiconductor layer causing conductorization and short circuits
Solution Approach 1:
The passivation layer is divided into multiple sub-layers (first passivation layer, second passivation layer, and third passivation layer) with different materials and functions. The first layer (SiOx) provides initial protection, the second layer (SiNx) acts as a hydrogen barrier, and the third layer (SiOx) provides final protection, thereby preventing hydrogen diffusion while maintaining device stability.
Solution Approach 2:
The silicon nitride layer (SiNx) is introduced as an intermediary barrier between the oxide semiconductor layer and the outer silicon oxide layers. This intermediate layer specifically blocks hydrogen ion diffusion while allowing the overall passivation structure to maintain electrical insulation and device protection.
2Reliability
If multiple barrier layers are added to prevent hydrogen diffusion, then device reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention optimizes specific parameters of the passivation layers including thickness (50-200nm for first and third layers, 50-100nm for second layer), material composition (SiOx with 1.9≤x≤2.1, SiNx with nitrogen content 60-80 at%), and deposition conditions to achieve effective hydrogen barrier performance while maintaining a relatively simple three-layer structure that balances reliability and manufacturing complexity.
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 composite passivation layer effectively prevents hydrogen diffusion to the active layer, enhancing the stability and performance of TFTs by reducing the likelihood of conductorization and short circuits, while also reducing production costs by eliminating the need for additional barrier layers.
Implementation Method 1
annealing the silicon oxynitride layer at an annealing temperature not higher than 250°C
Implementation Method 2
depositing a plurality of silicon oxide layers on an active metal oxide semiconductor layer of a transistor
Implementation Method 3
depositing a silicon oxynitride layer on the plurality of silicon oxide layers by using nitrogen monoxide and silane gases
Implementation Method 4
the hydrogen content in the first silicon oxide layer of the plurality of silicon oxide layers which is adjacent to the metal oxide semiconductor layer is higher than that in other silicon oxide layers
Data Source
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AI summary
The present disclosure provides a transistor, an array substrate and a method of manufacturing the array substrate, and a display device. The method of manufacturing the array substrate comprises: depositing a plurality of silicon oxide layers on an active layer of a transistor; and depositing a silicon oxynitride layer over the plurality of silicon oxide layers.