TFT Gate Insulator Layout for Stable Display Transistors
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Solution Overview
Problem
Existing display devices face challenges in ensuring the stability of thin-film transistors, which affects the reliability and performance of the devices.
Innovation Solution
A display device structure is proposed, featuring a substrate with a semiconductor layer divided into first and second areas, and a first gate insulating layer with a specific dielectric constant distribution, including a first insulating layer, a second insulating layer with a higher dielectric constant, and a third insulating layer. This configuration ensures stability by optimizing the equivalent oxide thickness and interatomic bonding energy across different transistor areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gate insulating layer with uniform dielectric constant is used, then the manufacturing process is simple, but the thin-film transistor stability is insufficient
Solution Approach 1:
The gate insulating layer is divided into three distinct insulating layers (first, second, and third) with different dielectric constants and thicknesses. This segmentation allows each layer to contribute differently to the overall electrical characteristics, enabling precise control of equivalent oxide thickness for both switching and driving transistors while maintaining manufacturing feasibility through sequential deposition processes.
Solution Approach 2:
The patent implements different dielectric constant values and thickness parameters for different regions of the gate insulating layer structure. The first insulating layer has a specific dielectric constant and thickness optimized for switching transistor performance, while the second and third layers have different parameters optimized for driving transistor performance. This local quality differentiation ensures that each transistor type receives the appropriate electrical characteristics without requiring completely separate structures.
2Object-generated harmful factors
If the gate insulating layer thickness is increased to reduce leakage current, then leakage current decreases, but the driving range of transistors is reduced
Solution Approach 1:
The patent changes the dielectric constant parameter across different insulating layers rather than simply increasing thickness uniformly. By using layers with progressively different dielectric constants (first layer with higher dielectric constant, second layer with intermediate, third layer with lower), the structure achieves effective leakage current reduction equivalent to a thicker uniform layer, while the cumulative thickness remains controlled to preserve transistor driving range. This parameter differentiation allows decoupling of leakage current control from thickness constraints.
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
The proposed solution enhances the stability and reliability of thin-film transistors, reducing leakage currents and maintaining the driving range of transistors, thereby improving the overall performance and stability of the display device.
Implementation Method 1
the second insulating layer is disposed between the first insulating layer and the third insulating layer, and has a dielectric constant greater than that of the third insulating layer
Data Source
AI summary
A display device is disclosed that includes a substrate, a semiconductor layer, a first conductive layer, and a first gate insulating layer. The semiconductor layer is disposed on the substrate and includes a first area and a second area. The first conductive layer is disposed on the semiconductor layer and includes a first gate pattern overlapping the first area and a second gate pattern overlapping the second area. The first gate insulating layer is disposed between the semiconductor layer and the first conductive layer and includes a first insulating layer overlapping the first area and the second area, a second insulating layer overlapping the first area and the second area, and a third insulating layer not overlapping the first area but overlapping the second area. The second insulating layer is disposed between the first insulating layer and the third insulating layer, and has a dielectric constant greater than that of the third insulating layer.