Organic Transistor Channel Definition via Selective Etching
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Solution Overview
Problem
Existing organic transistors face challenges in reducing the size of the organic semiconductor layer's channel portion and achieving high definition, while defective liquid crystal alignment occurs due to bulging edge parts.
Innovation Solution
A manufacturing method involving the formation of a gate electrode, gate insulating film, drain and source electrodes, a liquid crystal alignment film, and an opening part created by etching, followed by the deposition of an organic semiconductor film within the opening part, which allows for precise control of the channel portion's dimensions and reduces bulging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the organic semiconductor layer is formed by conventional methods to reduce its size, then the channel portion size is reduced, but the definition and alignment of the channel portion deteriorates
Solution Approach 1:
The patent segments the channel portion formation into distinct steps: first forming the organic semiconductor layer across the entire electrode region, then selectively removing material only from the channel region through etching. This segmentation allows the channel portion to be precisely defined after the layer is already formed, achieving both small size and high definition without the trade-off present in conventional simultaneous formation methods.
Solution Approach 2:
The organic semiconductor layer is formed in advance across the entire electrode area before the channel portion is specifically defined. This preliminary action of forming the complete layer first, then selectively removing portions, enables precise channel definition that would be difficult to achieve if attempting to form only the channel portion directly, thus resolving the contradiction between size reduction and definition maintenance.
2Manufacturing precision
If the channel portion is made smaller to achieve higher definition, then the definition improves, but bulging at the edge part occurs
Solution Approach 1:
The patent extracts and removes the excess organic semiconductor material from the channel region through selective etching after the layer has been formed. This extraction process precisely defines the channel boundaries without causing edge bulging, because the material is removed cleanly rather than being deposited in a way that creates edge effects. The result is high definition channel portions with clean edges and no bulging.
3Ease of manufacture
If conventional manufacturing methods are used, then the process is simpler, but the liquid crystal alignment becomes defective
Solution Approach 1:
The manufacturing process is segmented into distinct stages: organic semiconductor layer formation, etching to define channels, and liquid crystal alignment. This segmentation isolates the alignment step from the channel formation process, ensuring that the alignment film and liquid crystal can be properly prepared without interference from channel structure formation, thereby maintaining reliable alignment while keeping the overall process manageable.
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 method enables higher definition of the channel portion and minimizes bulging at the edge parts, improving the alignment and performance of the organic transistor and liquid crystal element.
Implementation Method 1
to form an opening part by dripping an etchant to a region of the liquid crystal alignment film that overlaps with the gate electrode in a plane view
Data Source
AI summary
To achieve higher definition of a channel portion of an organic transistor and to reduce bulging at the edge part of the channel portion. A manufacturing method of an organic transistor includes: forming a gate electrode on a substrate surface; forming a gate insulating film on the substrate surface to cover the gate electrode; forming a drain electrode and a source electrode with a predetermined distance therebetween on the gate insulating film surface and at a position where each electrode partially overlaps with the gate electrode; forming a liquid crystal alignment film on the gate insulating film surface to cover the drain electrode and the source electrode; forming an opening part by dripping an etchant to a region of the liquid crystal alignment film that overlaps with the gate electrode in a plane view; and forming an organic semiconductor film at the opening part of the liquid crystal alignment film.