3D Gate Electrode Structure for Display Device Kink Phenomenon
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Solution Overview
Problem
The reduction in pixel size of display devices leads to a higher likelihood of the kink phenomenon in thin film transistors, affecting current control and image quality due to the generation of hot electrons in intense electric fields, resulting in varied transistor characteristics.
Innovation Solution
The design includes thin film transistors with a semiconductor layer and a gate electrode configuration featuring multiple gate portions positioned above, below, and alongside the semiconductor layer, with insulating layers stacked around the semiconductor layer to prevent electrical connection between the gate and semiconductor, reducing the occurrence of kink phenomenon by allowing lower voltage driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to achieve high resolution, then display resolution is improved, but kink phenomenon occurs more frequently in thin film transistors
Solution Approach 1:
The gate electrode is divided into multiple segments: a first gate electrode portion above the semiconductor layer, a second gate electrode portion below the semiconductor layer, and a third gate electrode portion lateral to the semiconductor layer. This segmentation allows independent control of electric fields in different regions, reducing hot electron accumulation and kink phenomenon while maintaining the benefits of small pixel size for high resolution displays.
Solution Approach 2:
The invention extends the gate electrode control from traditional two-dimensional (above and below the channel) to three-dimensional configuration by adding a third gate electrode portion lateral to the semiconductor layer. This third dimension provides additional control over the electric field distribution, effectively suppressing kink phenomenon in miniaturized transistors while preserving high display resolution.
2Measurement precision
If pixel size is reduced, then display resolution is improved, but space for thin film transistor is reduced
Solution Approach 1:
By segmenting the gate electrode into three portions positioned at different locations relative to the semiconductor layer, the invention achieves effective transistor control within a reduced area. The segmented structure allows optimized electric field distribution that maintains transistor performance despite smaller pixel and transistor dimensions, enabling high resolution displays.
Solution Approach 2:
The third gate electrode portion lateral to the semiconductor layer utilizes the lateral dimension to provide additional control without increasing the vertical or planar footprint significantly. This three-dimensional gate configuration enables effective transistor operation in reduced space, supporting smaller pixel sizes for high resolution displays.
3Power
If intense electric field is generated at drain terminal, then current control capability is improved, but hot electrons are generated causing kink phenomenon
Solution Approach 1:
The gate electrode is segmented into three portions that can independently influence the electric field distribution in different regions of the transistor. The first gate electrode portion above the semiconductor layer, the second gate electrode portion below, and the third lateral portion work together to distribute and moderate the electric field intensity, maintaining current control capability while reducing hot electron generation at the drain terminal.
Solution Approach 2:
Different gate electrode portions are positioned to provide localized electric field control: the first gate electrode portion controls the region above the semiconductor layer, the second controls the region below, and the third controls the lateral region. This localized control allows optimization of current drive while suppressing intense electric fields that generate hot electrons, preventing kink phenomenon.
Data Source
AI summary
The purpose of the invention is suppressing a kink phenomenon and improving the image quality of a display device. The display device has a TFT in a pixel. The TFT has a semiconductor layer, a first insulating layer under the semiconductor layer, a second insulating layer over the semiconductor layer, and a gate electrode facing the semiconductor layer with a gap. The gate electrode has a first gate electrode portion facing a lower surface of the semiconductor layer, a second gate electrode portion facing an upper surface of the semiconductor layer, and a third gate electrode portion facing a lateral surface of the semiconductor layer and connected to the first and second gate electrode portions. A laminated part where the first and second insulating layers are stacked is around the semiconductor layer, and a part of the laminated part is between the lateral surface and the third gate electrode portion.