Thin-Film Transistor Sidewall Alignment for Channel Interface Control
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Solution Overview
Problem
Existing display devices, particularly organic light-emitting display devices, face challenges in achieving improved interface characteristics at the lower portion of the channel region of the active layer and varying the thickness of the active layer effectively.
Innovation Solution
The display device includes a thin-film transistor with a lower gate insulating film and an active layer aligned with its sidewalls, where the lower gate insulating film is made of silicon oxide with a higher oxygen content than the buffer layer, and the active layer is made of crystalline silicon, allowing for precise alignment and control over the active layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lower gate insulating film and active layer are formed with aligned sidewalls, then the interface characteristics at the channel region are improved, but the manufacturing precision requirements are increased
Solution Approach 1:
The lower gate insulating film is formed first with its sidewalls, and then the active layer is formed to align with these pre-established sidewalls. This preliminary formation of the gate insulating film structure provides a reference for subsequent active layer patterning, improving interface characteristics while managing precision requirements through sequential processing
Solution Approach 2:
The lower gate insulating film acts as an intermediary structure between the lower gate conductive layer and the active layer. By forming this intermediate layer with controlled sidewalls, the patent creates a buffer zone that improves interface characteristics and provides a reference structure for alignment, reducing the direct precision requirements between the conductive layer and active layer
2Reliability
If the oxygen content of the lower gate insulating film is increased, then the interface characteristics are improved, but the material composition control complexity is increased
Solution Approach 1:
The patent changes the oxygen content parameter of the lower gate insulating film material to improve interface characteristics. By controlling the oxygen content to be higher than in the buffer layer, the interface quality at the channel region is enhanced. This parameter adjustment is managed through controlled formation processes that deposit materials with specific compositional characteristics
3Adaptability or versatility
If the active layer thickness is varied, then the device performance flexibility is improved, but the manufacturing process complexity is increased
Solution Approach 1:
The patent introduces dynamic control over the active layer thickness, allowing the thickness to be varied according to different device performance requirements. This is achieved through controllable deposition or etching processes that can adjust the final thickness of the active layer, providing flexibility while managing process complexity through standardized variable parameter processes
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 enhances the interface characteristics at the channel region, improving the performance and flexibility of the display device by allowing for easier thickness variation of the active layer.
Implementation Method 1
the lower gate insulating film including an upper surface and sidewalls. The thin-film transistor may include an active layer disposed on the upper surface of the lower gate insulating film, the active layer including sidewalls. At least one of the sidewalls of the lower gate insulating film and at least one of the sidewalls of the active layer may be aligned with each other
Implementation Method 2
At least one of the sidewalls of the lower gate insulating film and at least one of the sidewalls of the active layer may be aligned with each other
Data Source
AI summary
A display device and method of fabricating the same are provided. The display device includes a substrate and a thin-film transistor formed on the substrate. The thin-film transistor includes a lower gate conductive layer disposed on the substrate, and a lower gate insulating film disposed on the lower gate conductive layer The lower gate insulating film includes an upper surface and sidewalls. The thin-film transistor includes an active layer disposed on the upper surface of the lower gate insulating film, the active layer including sidewalls. At least one of the sidewalls of the lower gate insulating film and at least one of the sidewalls of the active layer are aligned with each other.