Oxide TFT Gate Structure for Stable Short-Channel Vd-Id
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Solution Overview
Problem
The formation of a stable intermediate region between the channel and the drain/source in oxide semiconductor TFTs is challenging, especially when the channel length is short, leading to potential depletion and unstable TFT characteristics due to hydrogen diffusion.
Innovation Solution
A display device structure is implemented with a gate insulating film, an aluminum oxide film, a gate electrode, side spacers, and an interlayer insulating film, where the gate electrode length is shorter than the aluminum oxide film, forming an intermediate region and controlling hydrogen diffusion to stabilize the TFT characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the channel length is shortened to improve device integration, then the productivity is improved, but the TFT becomes more prone to depletion
Solution Approach 1:
The patent applies local quality by creating a non-uniform hydrogen concentration distribution along the device length, with the channel region specifically protected from hydrogen exposure. Even in short-channel devices, this localized control ensures the channel maintains appropriate resistance levels while drain and source regions achieve low resistance, enabling high integration without sacrificing TFT stability.
Solution Approach 2:
The patent applies preliminary action by forming the gate insulating film and controlling hydrogen supply before final device operation. By establishing the gate insulating film structure and controlling hydrogen introduction timing, the patent prevents channel depletion from occurring in the first place, enabling short-channel designs to achieve both high integration and 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
This structure effectively stabilizes the TFT characteristics by controlling hydrogen diffusion, reducing the risk of channel conductivity and fluctuating Vd-Id characteristics, especially in short channel lengths, thereby enhancing the reliability of oxide semiconductor TFTs.
Implementation Method 1
hydrogen is supplied to the drain region and the source region to give conductivity in those regions
Data Source
AI summary
The purpose of the present invention is to decrease the resistance of the drain and source in the TFT of the oxide semiconductor as well as to have stable Vd-Id characteristics of the TFT. The structure of the present invention is as follows: A display device having plural pixels including thin film transistors (TFT) having oxide semiconductor films comprising: a gate insulating film formed on the oxide semiconductor film, an aluminum oxide film formed on the gate insulating film, a gate electrode formed on the aluminum oxide film, a side spacer formed on both sides of the gate electrode, and an interlayer insulating film formed on the gate electrode, the side spacer, a drain and a source, wherein in a plan view, and in a direction from the drain to the source, a length of the gate electrode is shorter than a length of the aluminum oxide film.