Oxide Semiconductor TFT Layout for High Channel Resistance
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Solution Overview
Problem
The challenge is to maintain a high resistance in the channel region of oxide semiconductor thin film transistors while keeping the resistances of the source and drain regions low, as existing methods for supplying oxygen to the channel region inadvertently increase the resistances of these regions, reducing the ON current.
Innovation Solution
A semiconductor device design where an aluminum oxide film is formed on the gate insulating film, but it covers neither the drain nor the source region, and a block layer is used to prevent oxygen from reaching these regions, allowing oxygen to be supplied only to the channel region, thereby maintaining high channel resistance and low source and drain resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oxygen is supplied to the channel region of oxide semiconductor by forming an aluminum oxide film on 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 aluminum oxide film is segmented into two regions: a first aluminum oxide film covering the channel region to increase its resistance, and a second aluminum oxide film covering the source and drain regions to prevent oxygen supply and maintain low resistance. This segmentation allows different functional requirements of different regions to be satisfied simultaneously.
Solution Approach 2:
Different regions of the semiconductor device are given different oxygen supply characteristics. The channel region receives oxygen supply from the aluminum oxide film to increase resistance, while the source and drain regions are protected from oxygen supply by a separate aluminum oxide film to maintain low resistance. This local differentiation of properties resolves the contradiction between channel and source/drain region requirements.
2Ease of manufacture
If the aluminum oxide film covers the entire gate insulating film to supply oxygen, then oxygen supply is simplified, but the source and drain regions cannot maintain sufficiently low resistances
Solution Approach 1:
The aluminum oxide film structure is divided into two distinct parts: a first aluminum oxide film for oxygen supply to the channel, and a second aluminum oxide film to protect the source and drain regions. This segmentation maintains manufacturing simplicity while achieving precise regional control over resistance characteristics.
Solution Approach 2:
The second aluminum oxide film acts as an intermediary protective layer between the oxygen supply process and the source/drain regions. It mediates the oxygen supply by blocking oxygen from reaching the source and drain regions while allowing the first aluminum oxide film to supply oxygen to the channel region.
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 transistor characteristics of oxide semiconductor TFTs by ensuring high channel resistance and low source and drain resistances, improving the ON current performance.
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
Implementation Method 2
a block layer is used to prevent oxygen from reaching these regions
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.