ITO Electrodes Doped with Group III Elements for Organic Thin Film Transistors
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Solution Overview
Problem
The challenge is to fabricate thin film transistors and array substrates at low temperatures (≤200 degrees centigrade) using organic semiconductor materials, while overcoming issues with traditional metallic electrodes like gold, which have high work functions, poor adhesion, and high costs, and maintaining the semiconductor properties of silicon-based materials.
Innovation Solution
The use of indium-tin-oxide (ITO) doped with Group III elements, such as boron, as source and drain electrodes, which reduces the interface energy barrier with organic semiconductor layers, improves adhesion, and allows for precise line widths, along with the deposition of organic semiconductor materials at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metallic electrodes like gold are used, then high work function is achieved, but adhesion is poor and cost is high
Solution Approach 1:
The patent uses a composite electrode structure consisting of ITO (indium tin oxide) as the base layer and gold as the top layer. This composite structure combines the high work function of gold with the good adhesion and low cost characteristics of ITO, resolving the contradiction between achieving high work function and maintaining good adhesion with low cost.
Solution Approach 2:
ITO serves as an intermediary layer between the substrate and the gold layer. It provides good adhesion to the substrate while also serving as a platform for the gold layer to achieve the desired high work function, thus mediating between the requirements of adhesion and work function.
2Reliability
If silicon-based semiconductor materials are used, then good semiconductor properties are achieved, but fabrication temperature must be high (>200 degrees centigrade)
Solution Approach 1:
The patent changes the material parameter from traditional silicon-based semiconductors to organic semiconductor materials. This material substitution allows the semiconductor to be fabricated at low temperatures (≤200 degrees centigrade) while maintaining the necessary semiconductor properties for transistor operation.
3Adaptability or versatility
If low temperature deposition is used, then flexible substrates can be used, but traditional metallic electrodes cannot be formed
Solution Approach 1:
The patent changes the electrode material from traditional metals to ITO, which can be deposited at low temperatures. This material parameter change enables the use of flexible substrates while maintaining the ability to form functional electrodes through low temperature deposition 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 approach enables the formation of thin film transistors with improved properties, reduced product costs, and precise line widths, while maintaining the functionality of the organic semiconductor layer, even at low temperatures, making it suitable for flexible substrates.
Implementation Method 1
The use of indium-tin-oxide (ITO) doped with Group III elements, such as boron, as source and drain electrodes, which reduces the interface energy barrier with organic semiconductor layers
Implementation Method 2
deposition of organic semiconductor materials at low temperatures
Data Source
AI summary
Provided is a thin film transistor including a gate electrode on a substrate; a gate insulating layer on the gate electrode; source and drain electrodes including first source and drain layers on the gate insulating layer, respectively, and spaced apart from each other, wherein at lease one of the first source and drain layers includes indium-tin-oxide doped with at least one Group III element; and an organic semiconductor layer on the gate insulating layer and contacting the first source and drain layers.