Thin-Film Transistor Dual-Layer Insulator Oxygen Supply
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Solution Overview
Problem
The rate of forming oxide films in thin-film transistors is low, leading to prolonged manufacturing times and potential defects due to insufficient oxygen supply to the semiconductor layer.
Innovation Solution
A thin-film transistor structure is developed with a second insulating film comprising two regions: a low-argon, oxygen-supplying first layer and a high-argon, thicker second layer, formed using plasma CVD, which increases film growth rate and density, allowing for efficient oxygen distribution and reduced oxygen radical generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide film is formed to supply oxygen to the semiconductor layer, then electrical characteristics are adjusted, but manufacturing time is prolonged due to low film formation rate
Solution Approach 1:
The oxide film is divided into two distinct layers: a first oxide film in contact with the semiconductor layer that supplies oxygen, and a second oxide film formed at a higher rate with argon gas that does not supply oxygen. This segmentation allows the first layer to be thin (5-20 nm) for quick formation while the second layer provides the necessary oxygen supply function, resolving the contradiction between fast manufacturing and reliable electrical characteristics
Solution Approach 2:
Different regions of the oxide film structure are assigned different qualities and functions. The first oxide film region has high oxygen supply capability but low formation rate, while the second oxide film region has low oxygen supply capability but high formation rate. This local differentiation allows each region to optimize its specific function, achieving both fast manufacturing and reliable electrical characteristics
2Productivity
If argon gas is introduced during plasma CVD, then film growth rate and density increase, but oxygen supply capability decreases
Solution Approach 1:
The oxide film is segmented into two layers with different formation conditions: the first layer is formed without argon gas to ensure high oxygen supply capability, while the second layer is formed with argon gas to achieve high growth rate and density. This segmentation resolves the contradiction by assigning different formation methods to different functional regions
Solution Approach 2:
The argon gas concentration parameter is changed between the two oxide film formation processes. The first oxide film is formed with 0-10% argon gas to maintain oxygen supply capability, while the second oxide film is formed with 10-50% argon gas to maximize growth rate. This parameter change allows optimization of both productivity and reliability in different film regions
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 significantly shortens production time, stabilizes electrical characteristics, and allows for precise control of threshold voltage by adjusting the thickness ratio of the layers, reducing oxygen radical-induced defects.
Implementation Method 1
oxygen is supplied from the oxide film provided in contact with the semiconductor layer to the semiconductor layer
Implementation Method 2
formed using plasma CVD
Implementation Method 3
formed using plasma CVD
Data Source
AI summary
According to one embodiment, a thin-film transistor includes a first insulating film, an oxide semiconductor layer provided on the first insulating film and a second insulating film provided on the oxide semiconductor layer, and at least one of the first insulating film and the second insulating film includes a first region in contact with the oxide semiconductor layer and a second region further distant from the oxide semiconductor layer than the first region, and the second region has an argon concentration higher than that of the first region.