Fluorinated Insulating Polymer Gate Layer for Organic Semiconductor Reliability
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Solution Overview
Problem
Conventional organic semiconductor thin film transistors face issues with hygroscopicity and durability due to the use of polar resins in gate insulating layers, leading to moisture absorption, ion current flow, threshold voltage shifts, and dielectric breakdown.
Innovation Solution
An organic semiconductor element with a gate insulating layer and another insulating layer containing a fluorinated aromatic ring-based insulating polymer, which reduces hygroscopicity and prevents conductibility in the organic semiconductor layer, achieved through a liquid phase process using a solvent with high polarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polar resins (phenol-based or acryl-based) are used as gate insulating layer material, then ease of manufacture is improved, but hygroscopicity increases causing threshold voltage shift and dielectric breakdown
Solution Approach 1:
The patent changes the chemical composition parameters of the gate insulating layer by using fluorinated aromatic ring-based polymers instead of conventional polar resins. This parameter change reduces the dielectric constant and hygroscopicity while maintaining insulating properties, thereby improving reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The patent employs composite material design by combining fluorinated aromatic ring structures with specific polymer backbones. This composite approach creates a gate insulating layer that simultaneously achieves low hygroscopicity, appropriate dielectric constant, and good film-forming properties, resolving the contradiction between ease of manufacture and reliability.
2Reliability
If inorganic materials are used as gate insulating layer, then reliability is improved, but device complexity and manufacturing time increase due to vapor phase film forming
Solution Approach 1:
The patent substitutes the mechanical vapor phase deposition process with a liquid phase coating method. The fluorinated aromatic ring-based polymer can be applied through simple liquid coating techniques followed by drying, eliminating the need for complex vacuum equipment and multi-step processes while maintaining reliable insulating performance.
Solution Approach 2:
The patent changes the material state parameter from inorganic solid (requiring vapor phase deposition) to organic polymer (amenable to liquid phase processing). This parameter change enables simpler manufacturing while achieving comparable or superior reliability through the fluorinated structure's inherent low hygroscopicity.
3Ease of manufacture
If conventional resin materials are used for gate insulating layer, then ease of manufacture is improved, but moisture absorption increases leading to ion current and threshold voltage shift
Solution Approach 1:
The patent fundamentally changes the chemical parameter of the gate insulating layer by introducing fluorinated aromatic ring structures. This parameter change dramatically reduces the polarity and hygroscopicity of the material, preventing moisture absorption and ion current generation while maintaining ease of manufacture through liquid phase processing.
Solution Approach 2:
The patent converts the typically harmful polar groups in resin materials into beneficial low-polarity fluorinated structures. By replacing conventional polar resins with fluorinated aromatic ring-based polymers, the material's natural resistance to moisture is enhanced, turning potential moisture sensitivity into moisture resistance while keeping manufacturing simple.
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
The solution results in an organic semiconductor element with improved mechanical strength, reduced moisture absorption, and enhanced reliability, maintaining insulating properties while lowering operating voltage and preventing conductibility in the organic semiconductor layer.
Implementation Method 1
Since the insulating polymer with the main chain including repeating units represented by the above general formula (1) or (2) contains the fluorinated aromatic rings, it exhibits a low hygroscopic property
Implementation Method 2
achieved through a liquid phase process using a solvent with high polarity
Data Source
AI summary
The present invention provides an organic semiconductor element which has a low hygroscopic property and whose property is hardly deteriorated with time and an electronic device and electronic equipment each provided with such an organic semiconductor element and having high reliability. The organic semiconductor element of the present invention includes: a source electrode 20a; a drain electrode 20b; a gate electrode 50; a gate insulating layer 40; an organic semiconductor layer 30; and a buffer layer (another insulating layer) 60, wherein at least one of the gate insulating layer 40 and the buffer layer 60 contains an insulating polymer with a main chain having both end portions and including repeating units represented by the following general formula (1) or (2):where R1 and R2 are the same or different and each of R1 and R2 is a divalent linkage group, and Y is an oxygen atom or a sulfur atom.