Organic Thin Film Transistor With Auxiliary Gate Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current organic thin film transistors (TFTs) have low effective mobility and operation frequency due to high contact resistance between electrodes and organic semiconductors, especially at low gate voltages, limiting their performance compared to inorganic TFTs.
Innovation Solution
The design incorporates a main gate electrode and auxiliary gate electrodes separated by a gate insulating film, with the auxiliary gate electrodes having a stronger electric field than the main gate electrodes, to control contact and channel resistance, allowing for low voltage operation with increased mobility and frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the channel length L is shortened to enhance operation frequency, then the operation frequency increases, but the contact resistance at the interface between electrode and organic semiconductor increases and effective mobility decreases
Solution Approach 1:
The gate electrode is divided into two separate electrodes: a main gate electrode and an auxiliary gate electrode. The main gate electrode controls the channel region, while the auxiliary gate electrode is positioned adjacent to the source electrode to specifically control the contact region. This segmentation allows independent optimization of channel control and contact resistance reduction, resolving the contradiction between short channel length and contact resistance.
2Reliability
If a contact layer is formed between the gold electrode and substrate to reduce contact resistance, then contact resistance decreases, but parasitic resistance between source and drain electrodes and organic semiconductor layer increases
Solution Approach 1:
The auxiliary gate electrode acts as an intermediary element positioned between the source electrode and the organic semiconductor. By applying a positive voltage to the auxiliary gate electrode, it creates an accumulation layer that facilitates charge carrier injection and reduces contact resistance without requiring an additional contact layer material, thus avoiding increased parasitic resistance.
3Use of energy by moving object
If the gate voltage is kept low for low power operation, then power consumption decreases, but contact resistance increases and operation frequency decreases
Solution Approach 1:
Different gate voltages are applied to different regions of the transistor. The main gate electrode operates at a low voltage to minimize power consumption in the channel region, while the auxiliary gate electrode operates at a higher positive voltage to specifically reduce contact resistance at the source electrode interface. This local quality differentiation allows low power operation while maintaining low contact resistance.
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 configuration effectively reduces contact resistance and enhances the effective mobility of organic TFTs, enabling high-speed operation even at low voltages and short channel lengths, significantly improving their performance.
Implementation Method 1
the auxiliary gate electrodes having a stronger electric field than the main gate electrodes, to control contact and channel resistance
Data Source
AI summary
An organic thin film transistor includes an insulating substrate (1), gate electrodes (2, 4), a gate insulating film (3), an organic semiconductor film (5), and a source electrode (6) and a drain electrode (7). The gate electrodes include a main gate electrode (2) that is disposed in a region opposed to a channel region between the source electrode and the drain electrode in the organic semiconductor film, and a pair of auxiliary gate electrodes (4) that are disposed in respective regions opposed to the source electrode and the drain electrode on the two sides of the main gate electrode. The main gate electrode and the auxiliary gate electrodes are electrically separated from each other. The contact resistance between the source and drain electrodes and the organic semiconductor film is controlled so as to be at a low level even when the organic thin film transistor is driven in a low voltage region, and the operation frequency can be sufficiently enhanced due to the channel length being shortened.