Fluorine Polymer Interface for Organic Thin Film Transistor Mobility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic thin film transistors (OTFTs) face challenges with low charge carrier mobility, high driving voltage, and high threshold voltage compared to amorphous silicon TFTs, and existing solutions for improving gate insulating films are not suitable for organic semiconductors, limiting their application in flexible displays and requiring high-temperature fabrication processes.
Innovation Solution
A fluorine-based polymer thin film is formed at the interface between the gate insulating layer and the organic semiconductor layer, enabling OTFTs to be fabricated using conventional wet processes, which improves charge carrier mobility and reduces driving and threshold voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional inorganic gate insulating films (e.g., BST, Ta2O5, PZT) with high dielectric constant are used to reduce driving voltage, then driving voltage is reduced to -5V, but charge carrier mobility remains unsatisfactorily low at 0.06 cm2·V−1·sec−1 and fabrication requires high temperature (200-400°C)
Solution Approach 1:
The patent uses a composite gate insulating layer structure consisting of an inorganic insulating layer (e.g., SiO2, Si3N4) combined with an organic insulating layer containing fluorine-based polymer. This composite structure achieves high dielectric constant for low driving voltage while maintaining compatibility with organic semiconductors and enabling low-temperature fabrication. The fluorine-based polymer specifically improves charge carrier mobility at the interface between the gate insulating layer and organic semiconductor layer.
Solution Approach 2:
The patent changes the chemical composition and dielectric properties of the gate insulating layer by introducing fluorine-based polymer materials. This parameter change increases the effective dielectric constant at the interface, reduces threshold voltage, and improves charge carrier mobility from 0.06 to above 0.6 cm2·V−1·sec−1 while enabling fabrication at room temperature or low temperatures.
2Reliability
If inorganic gate insulating films are used to improve electrical insulating properties, then insulating properties are improved, but the fabrication process becomes complex and requires high temperature (200-400°C), limiting substrate choices
Solution Approach 1:
The patent changes the material parameters of the gate insulating layer by incorporating fluorine-based polymer materials that can be deposited at low temperatures. This enables fabrication on flexible plastic substrates that cannot withstand high temperatures, simplifies the manufacturing process, and maintains excellent electrical insulating properties through the high dielectric constant of the fluorine-containing compounds.
Solution Approach 2:
The fluorine-based polymer acts as an intermediary layer between the inorganic gate electrode and the organic semiconductor. This intermediary layer provides both excellent electrical insulation and chemical compatibility, enabling low-temperature processing while maintaining device performance. It mediates the interface between incompatible materials systems.
3Ease of manufacture
If conventional organic insulating films (polyimide, benzocyclobutene, photoacryls) are used, then ease of manufacture is improved, but device characteristics are unsatisfactory compared to inorganic insulating films
Solution Approach 1:
The patent creates a composite insulating system combining conventional organic insulating materials with fluorine-based polymer materials. This composite approach maintains the ease of manufacture and flexibility of organic materials while introducing the high dielectric constant and excellent electrical properties of fluorine-containing compounds, achieving both processability and high performance.
Solution Approach 2:
The patent enhances the dielectric parameters of organic insulating films by incorporating fluorine-based polymers. This parameter change increases the dielectric constant and improves charge carrier mobility at the interface, transforming conventional organic insulators into high-performance gate insulating layers that match or exceed inorganic film performance while retaining organic material advantages.
Data Source
AI summary
An organic thin film transistor including a fluorine-based polymer thin film and method of fabricating the same. The organic thin film transistor may include a gate electrode, a gate insulating layer, an organic semiconductor layer, source electrode, and a drain electrode formed on a substrate wherein a fluorine-based polymer thin film may be formed (or deposited) at the interface between the gate insulating layer and the organic semiconductor layer. The organic thin film transistor may have higher charge carrier mobility and/or higher on/off current ratio (Ion/Ioff). In addition, a polymer organic semiconductor may be used to form the insulating layer and the organic semiconductor layer by wet processes, so the organic thin film transistor may be fabricated by simplified procedure(s) at reduced costs.