Organic Passivation Layer for Transistor Reliability
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Solution Overview
Problem
Organic thin film transistors using organic semiconductor materials face reliability issues due to long-term bias stress, which causes shifts in threshold voltage and decreases in mobility, affecting their long-term performance and reliability.
Innovation Solution
An organic passivation layer composition is developed, comprising a cross-linked product with a specific mole ratio of cross-linking agent to hydroxyl groups, along with oligomer or polymer structural units, which are cured at a low temperature to form a passivation layer that enhances the reliability of organic thin film transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If an organic thin film transistor is driven for long time, then the device operates continuously, but threshold voltage shifts and mobility decreases due to bias stress
Solution Approach 1:
A passivation layer is formed on the organic semiconductor layer before the device is put into operation. This passivation layer is created through a preliminary process that prevents threshold voltage shifts and mobility degradation from occurring during long-term operation, thereby maintaining device reliability over extended periods
Solution Approach 2:
The passivation layer acts as an intermediary protective layer between the organic semiconductor layer and the external environment. It mediates the interaction by blocking harmful factors such as moisture and oxygen from reaching the semiconductor, thus preventing bias stress effects during continuous operation
2Reliability
If a passivation layer is formed to improve reliability, then threshold voltage stability improves, but the fabrication process becomes more complex
Solution Approach 1:
The passivation layer formation process is merged with existing fabrication steps. The cross-linking process that creates the passivation layer is integrated into the existing thermal processing steps already used in organic thin film transistor fabrication, thereby improving threshold voltage stability without significantly increasing process complexity
Solution Approach 2:
The passivation layer is formed by changing the physical-chemical parameters of the organic semiconductor layer through controlled cross-linking. By adjusting parameters such as temperature and cross-linking agent concentration, the passivation layer is created to improve threshold voltage stability while maintaining compatibility with existing fabrication processes
3Reliability
If a cross-linked passivation layer is formed to protect the organic semiconductor, then long-term reliability improves, but the manufacturing process requires additional steps
Solution Approach 1:
The passivation layer is formed through a self-service mechanism where the organic semiconductor layer itself undergoes cross-linking to create the protective layer. This self-passivation approach eliminates the need for separate protective layer deposition steps, thereby improving long-term reliability while maintaining manufacturing simplicity
Solution Approach 2:
The cross-linking process is achieved by changing parameters such as temperature and exposure time to activate the cross-linking reaction. This parameter-based approach allows the passivation layer to be formed using existing manufacturing equipment and processes, avoiding the need for additional manufacturing steps while improving long-term reliability
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 organic passivation layer effectively limits changes in threshold voltage and charge mobility over time, improving the long-term reliability of organic thin film transistors without compromising their electrical characteristics.
Implementation Method 1
an organic passivation layer composition including a cross-linking agent, the cross-linking agent being reacted in an amount such that the mole ratio of the cross-linking functional group(s) of the crosslinking agent to the hydroxyl group(s) of the structural unit
Implementation Method 2
The organic passivation layer effectively limits changes in threshold voltage and charge mobility over time, improving the long-term reliability of organic thin film transistors
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
According to example embodiments, an organic passivation layer composition includes a cross-linking agent and an oligomer or a polymer including structural units represented by the following Chemical Formula 1 and 2: In Chemical Formulae 1 and 2, each substituent is defined in the detailed description.