Composite Oxide-Silicon Thin-Film Transistor for Stable High Mobility
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Solution Overview
Problem
Current thin-film transistors face challenges in achieving good electrical stability and high mobility, particularly in high-resolution mobile display devices, due to limitations in amorphous silicon and polycrystalline silicon transistors, and oxide semiconductor transistors have relatively low stability and mobility compared to polycrystalline silicon transistors.
Innovation Solution
A thin-film transistor design featuring a silicon semiconductor layer sandwiched between two oxide semiconductor layers, with a gate electrode partially overlapping the semiconductor layer, where the oxide semiconductor layers include gallium and are formed using metal-organic chemical vapor deposition (MOCVD) to enhance stability and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If oxide semiconductor layers are used as the active layer, then manufacturing cost is reduced and low-temperature processing is enabled, but electron mobility and stability are relatively low compared to polycrystalline silicon transistors
Solution Approach 1:
The patent employs a composite semiconductor layer structure consisting of oxide semiconductor layers (first and second layers) with a silicon semiconductor layer positioned between them. This composite structure combines the advantages of oxide semiconductors (low-temperature processing, transparency) with silicon's high mobility and stability, thereby achieving both ease of manufacture and high reliability
2Reliability
If polycrystalline silicon is used as the active layer, then electron mobility and stability are improved, but manufacturing cost increases due to additional crystallization steps and high-temperature processing
Solution Approach 1:
The patent uses a composite structure where oxide semiconductor layers provide the base structure and low-temperature processing capability, while the embedded silicon semiconductor layer contributes high electron mobility and stability. This eliminates the need for high-temperature crystallization steps required by pure polycrystalline silicon, thereby reducing manufacturing cost while maintaining high reliability
3Productivity
If amorphous silicon is used as the active layer, then manufacturing time is reduced and cost is lowered, but electron mobility is low and threshold voltage changes occur
Solution Approach 1:
The patent combines oxide semiconductor layers with a silicon semiconductor layer to create a composite structure that maintains the quick deposition advantage of amorphous materials while introducing silicon's high mobility and stability. The oxide semiconductor provides rapid formation capability, while the silicon layer ensures consistent electrical properties and prevents threshold voltage drift
4Illumination intensity
If oxide semiconductor thin-film transistor is used, then transparency is achieved favorable for transparent displays, but electron mobility and stability are lower than polycrystalline silicon transistors
Solution Approach 1:
The patent maintains transparency by using oxide semiconductor layers which are inherently transparent, while embedding a silicon semiconductor layer between them to provide high electron mobility and stability. The composite structure preserves the optical properties of oxide semiconductors while compensating for their electrical limitations through the silicon component
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 improves electrical stability and maintains high mobility, enabling better performance in high-resolution displays by stabilizing the oxide semiconductor layers and preventing carrier concentration increases due to light exposure, thus maintaining consistent threshold voltage and driving properties.
Implementation Method 1
the oxide semiconductor layers include gallium and are formed using metal-organic chemical vapor deposition (MOCVD) to enhance stability and electrical properties
Data Source
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AI summary
A thin-film transistor, a display device including a thin-film transistor, and a method of manufacturing a thin-film transistor are provided. A thin-film transistor includes: a semiconductor layer including: a first oxide semiconductor layer including gallium (Ga), a second oxide semiconductor layer, and a silicon semiconductor layer between the first oxide semiconductor layer and the second oxide semiconductor layer, and a gate electrode spaced apart from the semiconductor layer and partially overlapping at least a part of the semiconductor layer.