Array Substrate Active Layer Carrier Adjustment for Threshold Voltage Compensation
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Solution Overview
Problem
The large difference in channel width-to-length ratio of thin film transistors in different regions of an array substrate leads to significant variations in threshold voltage, causing circuit failure due to either excessively low or high threshold voltages in certain regions.
Innovation Solution
The solution involves forming first and second thin film transistors with active layers having different carrier mobilities and concentrations, where the first active layer has a greater carrier mobility and concentration than the second active layer, and is positioned further away from the base substrate, with the second active layer located within a groove in the insulation layer, to compensate for the threshold voltage difference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thin film transistors with different channel width-to-length ratios are used in different regions, then the transistors can be optimized for their specific functions, but the threshold voltage varies significantly causing circuit failure
Solution Approach 1:
The patent applies local quality by forming different active layer structures in different regions. Specifically, a first active layer with first carrier concentration is formed in a first region, while a second active layer with second carrier concentration is formed in a second region. This allows each region to have optimized electrical characteristics suitable for its specific function while maintaining overall circuit reliability.
Solution Approach 2:
The patent changes the carrier concentration parameter of the active layer to compensate for threshold voltage variations. By adjusting the carrier concentration (first carrier concentration vs. second carrier concentration) in different regions, the invention compensates for the threshold voltage differences caused by varying channel width-to-length ratios, ensuring proper circuit operation.
2Reliability
If the carrier concentration is increased to reduce threshold voltage, then the threshold voltage difference is compensated, but the manufacturing process becomes more complex
Solution Approach 1:
The patent implements preliminary action by forming the first active layer with the first carrier concentration in the first region before forming the second active layer with the second carrier concentration in the second region. This sequential approach allows for controlled modification of carrier concentrations during the manufacturing process, compensating for threshold voltage differences while managing process complexity.
Data Source
AI summary
An array substrate, a manufacturing method thereof, and a display device are provided. The array substrate includes: a base substrate; a first thin film transistor located on the base substrate and including a first active layer; and a second thin film transistor located on the base substrate and including a second active layer; a matrix material of the first active layer is the same as that of the second active layer, and the first active layer and the second active layer satisfy at least one of the following conditions: a carrier mobility of the first active layer is greater than that of the second active layer, and a carrier concentration of the first active layer is greater than that of the second active layer. The array substrate is employed to compensate a difference in threshold voltage caused by a difference in channel width-to-length ratio of different thin film transistors.