Oxide Semiconductor Display Transistors With Hydrogen-Blocking Gates
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Solution Overview
Problem
Hydrogen diffusion from insulating films affects the active layers of transistors in display devices, leading to reduced effective channel length and unstable threshold voltage in oxide semiconductor transistors, compromising driving reliability.
Innovation Solution
Incorporating a first type transistor with a polysilicon active layer and a second type transistor with an oxide semiconductor layer, along with electrode patterns and light-shielding patterns, to capture and block hydrogen diffusion, thereby stabilizing the potential and preventing hydrogen from reaching the second type transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second type transistor with an oxide semiconductor active layer is used, then driving reliability is improved, but hydrogen diffusion from insulating films causes threshold voltage instability and reduced effective channel length
Solution Approach 1:
A first type transistor with a polysilicon active layer is introduced as an intermediary structure between the insulating film and the second type transistor. The polysilicon active layer acts as a barrier that captures hydrogen atoms, preventing them from diffusing into the oxide semiconductor active layer of the second type transistor, thereby maintaining threshold voltage stability and effective channel length.
2Reliability
If electrode patterns are added to block hydrogen diffusion, then hydrogen capture effectiveness is improved, but device complexity and manufacturing process difficulty increase
Solution Approach 1:
The electrode patterns are merged with the existing gate electrode structures of the first type transistor. The gate electrode serves dual functions: controlling the polysilicon active layer and acting as a hydrogen barrier. This integration avoids adding separate hydrogen blocking structures, thereby preventing increases in device complexity and manufacturing difficulty while maintaining effective hydrogen capture.
3Reliability
If electrode patterns are added to stabilize potential and block hydrogen, then hydrogen capture is improved, but additional manufacturing processes and materials are required
Solution Approach 1:
The electrode patterns are designed to perform multiple functions simultaneously: electrical potential stabilization and hydrogen diffusion blocking. By making the electrode structure multi-functional, the invention avoids the need for separate hydrogen barrier layers or additional stabilization structures, thereby maintaining manufacturing simplicity while achieving improved hydrogen capture effectiveness.
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 effectively prevents hydrogen diffusion, maintains channel length, and enhances driving stability and reliability of the display device without additional processes or materials, reducing greenhouse gas emissions.
Implementation Method 1
electrode patterns overlapping with a gate electrode are located in an upper layer and a lower layer of the second active layer to capture hydrogen between a first type transistor and the second type transistor
Data Source
AI summary
A display device includes a substrate comprising an active area and a non-active area, and a power voltage line and a gate driver disposed in the non-active area of the substrate and adjacent to each other. In the display device, the gate driver includes a first type transistor including a first active layer on the substrate, a first gate insulating film on the first active layer, and a first gate electrode overlapping the first active layer and located on the first gate insulating film, a second type transistor including a second active layer farther from the substrate than the first gate electrode, a second gate insulating film on the second active layer, and a second gate electrode overlapping the second active layer and located on the second gate insulating film, and a first electrode pattern overlapping the first gate electrode and located on the second gate insulating film.