TFT Dual-Gate Segmented Sub-Gates Stabilize Energy Band
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Solution Overview
Problem
The reliability and electrical performance of Thin-Film Transistors (TFTs) in display panels are compromised due to unstable threshold voltage drift caused by photo current generation in oxide TFTs, leading to poor display quality and reduced reliability.
Innovation Solution
Incorporating a second gate with at least two sub-gates that overlap the channel region, which, along with the primary gate, maintains a stable energy band by alternating signal polarities to control the channel region, thereby stabilizing switching characteristics and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional TFT structure with a single gate is used, then the device complexity is low, but the reliability and electrical performance are poor due to unstable threshold voltage drift
Solution Approach 1:
The gate is segmented into a first gate and a second gate with multiple sub-gates. The first gate controls the entire channel region, while the second gate controls a portion of the channel region. This segmentation allows independent control of different channel regions, enabling compensation for threshold voltage drift and improving reliability without excessive complexity increase.
Solution Approach 2:
The patent introduces a new spatial dimension by placing the second gate adjacent to the first gate, both overlapping the channel region. This dual-gate configuration adds a new control dimension that enables stabilization of the energy band and threshold voltage, addressing the reliability issue while maintaining reasonable device complexity.
2Reliability
If oxide semiconductor is used in the active layer, then the electrical performance can be improved, but photo current generation causes threshold voltage drift and reduces reliability
Solution Approach 1:
The patent converts the harmful photo current effect into a beneficial control mechanism. By using the second gate to apply compensation voltages that counteract the photo current-induced threshold voltage drift, the harmful effect is transformed into an opportunity for active stabilization of the energy band and improved electrical performance stability.
3Stability of the object's composition
If the second gate with multiple sub-gates is added, then the switching characteristics are stabilized, but the device complexity increases
Solution Approach 1:
The second gate is divided into multiple sub-gates, each controlling a specific portion of the channel region. This segmentation enables precise local control to stabilize switching characteristics while keeping each sub-gate structure simple and manageable, balancing stability improvement with controlled 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
This configuration ensures stable switching characteristics and improved electrical performance of TFTs, reducing threshold voltage drift and increasing reliability, resulting in enhanced display quality.
Implementation Method 1
the first gate and the second gate maintain an energy band of the channel region of the TFT at a relatively stable state
Data Source
AI summary
A TFT, a method for driving TFT, an array substrate, and a display device are disclosed. The TFT comprises a first gate on a base plate, an active layer insulated from the first gate, a source and a drain, and a second gate arranged on a side of the active layer away from the first gate and insulated from the active layer. The second gate comprises at least two sub-gates. An orthographic projection of each sub-gate overlaps that of a channel region. The first gate is capable of controlling the complete channel region, and the second gate is capable of controlling a portion of the channel region. The first and second gates maintain an energy band of the channel region at a relatively stable state, and thus maintain stable switching characteristics. This increases reliability and electrical performance of TFT.