IGZO Thin Film Transistor Stacked Active Layer
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Solution Overview
Problem
Current top-gate Indium Gallium Zinc Oxide (IGZO) thin film transistors (TFTs) face challenges in balancing high mobility and uniformity, leading to poor performance in display panels.
Innovation Solution
A thin film transistor with an active layer comprising stacked structures of N-layer indium oxidation layers, gallium oxidation layers, and zinc oxidation layers, manufactured using atomic layer deposition, which improves electron concentration and mobility, and enhances uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional top-gate IGZO TFT structure is used, then the manufacturing process is simple with lower mask usage, but the device cannot achieve both high mobility and high uniformity simultaneously
Solution Approach 1:
The active layer is segmented into multiple thin sub-layers (first active layer, second active layer, third active layer) with different compositions and functions. The first active layer provides high electron concentration, the second provides high mobility, and the third provides protection and uniformity. This segmentation allows each layer to be optimized independently for its specific function, resolving the contradiction between manufacturing simplicity and device uniformity.
Solution Approach 2:
The patent uses composite material structure with different oxide materials (indium oxide, gallium oxide, zinc oxide) in different layers. Each material is selected for its specific properties: indium oxide for high electron concentration, gallium oxide for high mobility, and zinc oxide for protection and uniformity. This composite approach enables simultaneous achievement of high mobility and high uniformity while maintaining relatively simple manufacturing processes.
2Ease of manufacture
If the active layer uses a single-layer structure, then the manufacturing process is simpler, but the electron concentration and mobility are insufficient
Solution Approach 1:
The active layer is divided into three distinct sub-layers, each with specific thickness and composition ratios. The first active layer (indium oxide dominant) provides high electron concentration, the second active layer (gallium oxide dominant) provides high mobility, and the third active layer (zinc oxide dominant) provides protection and uniformity. This segmentation enables each layer to contribute its specific property, achieving high reliability without excessive manufacturing complexity.
Solution Approach 2:
The patent optimizes specific parameters for each layer including thickness (50-200 nm range), composition ratios (metal oxide ratios), and deposition conditions. By carefully controlling these parameters, each layer achieves its optimal performance contribution, enabling high electron concentration and mobility while keeping the overall structure manageable for manufacturing.
3Reliability
If the indium oxidation layer thickness is increased to improve electron concentration, then the mobility decreases due to reduced uniformity
Solution Approach 1:
Instead of using a single thick indium oxide layer, the patent segments the indium oxide content into the first active layer (providing electron concentration) and distributes additional indium oxide in the second and third layers. Each layer maintains optimal thickness (50-200 nm) for uniformity while collectively providing high electron concentration. This segmentation resolves the contradiction between electron concentration and uniformity.
Solution Approach 2:
Different regions of the active layer structure have different local compositions optimized for their specific functions. The first active layer has high indium oxide content for electron concentration, the second has high gallium oxide content for mobility, and the third has zinc oxide for protection. This local quality optimization allows high electron concentration in specific regions without compromising overall film uniformity.
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
The solution significantly improves the mobility and uniformity of the thin film transistor, resulting in enhanced performance of the TFT and the associated display panels.
Implementation Method 1
the active layer is disposed on the buffer layer by an atomic layer deposition method
Data Source
AI summary
A thin film transistor is provided. The thin film transistor includes an active layer, and the active layer includes a plurality of stacked structures, and each of the stacked structures includes: a N-layer indium oxidation layer; a gallium oxidation layer, the gallium oxidation layer is provided on the indium oxidation layer of the N-layer indium oxidation layer; and a zinc oxidation layer is provided on the gallium oxidation layer. These stacked structures improve the performance of the thin film transistor. A preparation method of the thin film transistor and a display panel containing the thin film transistor is also provided.