Oxide Semiconductor Thin Film Transistor with Titanium Clusters
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Solution Overview
Problem
Conventional thin film transistors using oxide semiconductors face challenges in achieving high field effect mobility while maintaining low off-current, especially in large-screen or high-definition liquid crystal display devices, where increased drive current is required.
Innovation Solution
Incorporating titanium clusters with higher electrical conductance than the oxide semiconductor layer between the oxide semiconductor layer and the gate insulating layer, and optionally using a buffer layer with n-type conductivity, to enhance carrier concentration and mobility while suppressing off-current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxide semiconductor is used for thin film transistor channel formation region, then large area fabrication and low temperature processing are enabled, but field effect mobility is insufficient for high-definition display applications
Solution Approach 1:
The patent uses a composite structure combining oxide semiconductor layer with metal cluster layers (titanium, nickel, or their alloys). The metal clusters are embedded within or on the oxide semiconductor layer to create a composite material that enhances carrier mobility while maintaining the low-temperature processing advantages of oxide semiconductors. This composite approach allows achieving high field effect mobility (>10 cm²/Vs) necessary for high-definition displays while preserving the manufacturability benefits.
Solution Approach 2:
The patent introduces metal clusters at specific locations within the oxide semiconductor layer to locally enhance electrical properties. The metal clusters are strategically positioned in the channel formation region to improve carrier mobility where needed, while other regions maintain the inherent advantages of oxide semiconductor. This localized enhancement allows achieving high performance without compromising the overall low-temperature processing capability.
2Ease of manufacture
If conventional oxide semiconductor thin film transistor is used, then manufacturing is simplified, but off-current is too high for reliable switching operation
Solution Approach 1:
The patent incorporates metal cluster layers (titanium, nickel, or their alloys) within the oxide semiconductor structure to create a composite material that suppresses off-current. The metal clusters form conductive pathways that enable better control over carrier flow, reducing leakage current while maintaining the relatively simple manufacturing process of oxide semiconductor deposition at low temperatures.
Solution Approach 2:
The metal clusters act as intermediary elements between the source/drain electrodes and the gate control region. They serve as a mediating layer that improves the electrical interface, enabling better control over the channel formation and reducing off-state leakage while maintaining ease of manufacture through conventional sputtering or evaporation techniques.
3Reliability
If metal clusters are added to oxide semiconductor layer, then field effect mobility is enhanced, but device structure becomes more complex
Solution Approach 1:
The patent divides the semiconductor layer into multiple functional segments: the oxide semiconductor matrix and embedded metal cluster regions. This segmentation allows each component to perform its specific function - the oxide semiconductor provides the base channel formation with low-temperature processing capability, while the metal clusters provide localized mobility enhancement. The segmented structure achieves high field effect mobility without requiring complete restructuring of the entire device.
Solution Approach 2:
The metal clusters are nested within the oxide semiconductor layer or positioned in direct contact with it, creating a nested structure where the metal clusters are embedded in or on the semiconductor matrix. This nesting approach integrates the mobility-enhancing metal clusters into the existing oxide semiconductor structure without adding significant external complexity, maintaining a compact and manufacturable device architecture.
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 increases field effect mobility of the thin film transistor and suppresses off-current, enabling high-performance and reliable operation in display devices, particularly in large-screen or high-definition applications.
Implementation Method 1
Incorporating titanium clusters with higher electrical conductance than the oxide semiconductor layer between the oxide semiconductor layer and the gate insulating layer
Data Source
AI summary
In forming a thin film transistor, an oxide semiconductor layer is used and a cluster containing a titanium compound whose electrical conductance is higher than that of the oxide semiconductor layer is formed between the oxide semiconductor layer and a gate insulating layer.