Oxide TFT Gate Stack Layout for Channel and Contact Resistance Control
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Solution Overview
Problem
The existing methods for manufacturing thin film transistors (TFTs) using oxide semiconductors face challenges in achieving a high resistance in the channel region while maintaining low resistances in the source and drain regions, which affects the ON current of the TFT.
Innovation Solution
The proposed solution involves forming a gate insulating film on the oxide semiconductor, followed by an aluminum oxide film that covers only the channel region and not the source and drain regions. This configuration allows for the selective supply of oxygen to the channel region, thereby increasing its resistance, while preventing oxygen from reaching the source and drain regions, thus maintaining their low resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oxygen is supplied to the entire surface of the gate insulating film, then the resistance of the channel region is increased, but the resistances of the source and drain regions also increase, reducing the ON current
Solution Approach 1:
The patent applies local quality by forming the aluminum oxide film selectively only over the channel region of the gate insulating film, not the entire surface. This localized approach allows oxygen to be supplied precisely where needed (channel region) to increase resistance, while preventing oxygen supply to source and drain regions, thereby maintaining their low resistance and ensuring high ON current.
2Manufacturing precision
If the aluminum oxide film covers the source and drain regions, then oxygen supply to these regions increases their resistance, but this reduces the ON current of the TFT
Solution Approach 1:
The aluminum oxide film is formed with a specific pattern that covers only the channel region and excludes the source and drain regions. This local quality approach creates different oxygen supply conditions in different regions: the channel region receives oxygen to increase resistance for proper switching characteristics, while source and drain regions remain oxygen-free to maintain low resistance for high current flow.
Solution Approach 2:
The gate insulating film surface is segmented into different zones: the channel region zone where aluminum oxide film is formed for oxygen supply, and the source/drain region zones where no aluminum oxide film is formed. This segmentation allows independent control of resistance characteristics in different functional regions of the TFT.
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 approach effectively enhances the resistance of the channel region while keeping the source and drain regions with low resistances, thereby improving the ON current of the TFT and achieving favorable transistor characteristics.
Implementation Method 1
oxygen is supplied to a region on the first insulating layer of the semiconductor layer from the first insulating layer through thermal treatment
Data Source
AI summary
An object of the present invention is to provide a technology using which, in a thin film transistor using oxide semiconductor, the resistance of a channel region of the oxide semiconductor is made high, and at the same time the resistances of a source region and a drain region of the oxide semiconductor are made low. There is provided a semiconductor device including: a thin film transistor including oxide semiconductor, the oxide semiconductor including a channel region, a drain region, and a source region; a gate insulating film formed on the channel region; an aluminum oxide film formed on the gate insulating film; and a gate electrode formed on the aluminum oxide film, wherein the aluminum oxide film has a region that covers neither the drain region nor the source region in a plane view.