Thin Film Transistor Source Drain Segmentation for Short Circuit Repair
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Solution Overview
Problem
In the fabrication of active-matrix liquid crystal display array substrates, short circuits frequently occur between the source and drain electrodes of thin film transistors, leading to decreased yield due to the simultaneous patterning process used for these electrodes, resulting in defective pixel units.
Innovation Solution
The thin film transistor design includes independent first and second source or drain electrode portions, which are electrically connected to the active layer, allowing for multiple parallel conductive channels between the data line and pixel electrode, enabling targeted repair of short circuits by cutting off specific conductive channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single patterning process is used to form source and drain electrodes simultaneously, then the fabrication process is simplified, but short circuits occur between source and drain electrodes
Solution Approach 1:
The source electrode is divided into a first source electrode portion and a second source electrode portion that are independent from each other. This segmentation allows the source electrode to be electrically isolated into separate conductive regions, preventing short circuits between source and drain while maintaining the simplified single-layer structure formed in the patterning process.
2Reliability
If repair is performed by cutting off the source electrode connection, then short circuit is eliminated, but the pixel unit becomes a dark spot and yield decreases
Solution Approach 1:
By dividing the source electrode into multiple independent portions, the invention enables selective repair strategies. When a short circuit occurs, only the defective source electrode portion needs to be cut off or repaired, while other portions remain functional. This segmentation prevents complete pixel failure, maintaining light emission capability and improving overall yield.
Solution Approach 2:
The independent source electrode portions allow for localized repair actions. Instead of rendering the entire pixel unit non-functional, the repair can be confined to the specific defective region (first or second source electrode portion), preserving the functionality of other regions and maintaining pixel operation.
3Ease of repair
If multiple independent source electrode portions are used, then repair flexibility is improved, but device structure becomes more complex
Solution Approach 1:
The first and second source electrode portions are merged into a single continuous source electrode layer that is formed in one patterning step. This combining approach maintains structural simplicity at the fabrication level while still providing the electrical separation needed for repair flexibility, as the portions remain electrically independent despite being in the same layer.
Data Source
AI summary
Embodiments of the present disclosure disclose a thin film transistor, a fabrication method thereof, a repair method thereof, and an array substrate. The thin film transistor comprises a gate electrode (12), a gate insulating layer (13), an active layer (14), a source electrode (16) and a drain electrode (17). The source electrode (16) comprises a first source electrode portion (161) and a second source electrode portion (162) independent from each other, the first source electrode portion (161) and the second source electrode portion (162) are electrically connected with the active layer (14), respectively; and/or, the drain electrode (17) comprises a first drain electrode portion (171) and a second drain electrode portion (172) independent from each other, the first drain electrode portion (171) and the second drain electrode portion (172) are electrically connected with the active layer (14), respectively.