TFT Light Blocking Gate Edge Structure
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Solution Overview
Problem
Low-temperature polycrystalline silicon Thin Film Transistors (TFTs) in OLED display panels are susceptible to performance degradation due to light exposure, particularly ultraviolet light, which affects the active region of the TFT during fabrication, leading to instability and performance issues.
Innovation Solution
A light blocking portion is formed above the edge of the gate in the TFT, using materials like molybdenum, titanium, or copper, to prevent light from entering the active region, with a projection width of the light blocking portion ranging from 4 μm to 20 μm, effectively blocking light and reducing diffraction effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light blocking portion is added above the gate edge, then light-induced degradation is reduced and TFT performance is improved, but device structure complexity increases
Solution Approach 1:
The gate structure is segmented by adding a separate light blocking portion above the gate edge, dividing the protective function into distinct components: the gate itself and the dedicated light blocking portion. This segmentation allows the light blocking function to be independently optimized without modifying the gate's primary electrical function.
Solution Approach 2:
The light blocking portion acts as an intermediary element between the incoming light and the active region. It intercepts and blocks ultraviolet and visible light before these wavelengths can reach and degrade the active region, thereby protecting the TFT performance without interfering with the gate's electrical operation.
2Object-affected harmful factors
If the projection width of the light blocking portion is increased to improve light blocking effectiveness, then light-induced degradation is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The projection width of the light blocking portion is optimized to a specific range (4-20 μm) that balances light blocking effectiveness with manufacturing feasibility. This parameter optimization ensures sufficient light blocking while remaining within the capabilities of standard photolithography and etching processes.
Solution Approach 2:
The light blocking portion extends slightly beyond the minimum required width to ensure adequate protection. The projection width is designed to be larger than the absolute minimum needed for light blocking, providing a margin that accounts for manufacturing variations while still meeting performance requirements.
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
This solution significantly improves the performance of the thin film transistor by reducing light-induced degradation, enhancing the stability and reliability of the TFTs in OLED display panels.
Implementation Method 1
forming a light blocking portion on the first insulation layer, the light blocking portion being arranged above an edge portion of the gate, so that the light blocking portion may block light entering the active layer from the edge portion of the gate
Data Source
AI summary
The embodiments of the present disclosure relate to an array substrate, a thin film transistor, methods for fabricating the same, and a display device. The method for fabricating the array substrate provided by the embodiments of the present disclosure comprises: forming an active layer on a substrate; forming a gate on the active layer; forming a first insulation layer on the gate; forming a light blocking portion on the first insulation layer, the light blocking portion being arranged above an edge portion of the gate, so that the light blocking portion blocks light entering the active layer from the edge portion of the gate.