Multilayered Oxide Semiconductor TFT for Leakage Current Reduction
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Solution Overview
Problem
Conventional thin-film transistors (TFTs) used in liquid crystal displays (LCDs) have low electron mobility and are prone to leakage current due to reactivity with blue light, leading to increased turn-off voltage over time.
Innovation Solution
A display substrate with a gate interconnection and an oxide semiconductor pattern comprising a first and second oxide semiconductor layer, where the first oxide semiconductor layer has a higher band gap to prevent blue light incidence and reduce leakage current, and a data interconnection to interconnect the gate interconnection, enhancing TFT stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oxide semiconductor is used to improve electron mobility, then electron mobility is improved, but leakage current increases due to reactivity with blue light
Solution Approach 1:
The oxide semiconductor layer is divided into multiple layers with different compositions and functions. The first oxide semiconductor layer (e.g., In-Ga-Zn-O) serves as the main channel layer for high electron mobility, while the second oxide semiconductor layer (e.g., In-Zn-O) with higher band gap acts as a protective layer to prevent blue light incidence and reduce leakage current.
Solution Approach 2:
The patent uses composite oxide semiconductor structures combining different metal oxides (In2O3, Ga2O3, ZnO) in specific ratios to achieve both high electron mobility and high band gap characteristics. The composite structure allows simultaneous optimization of electrical and optical properties that cannot be achieved with single materials.
2Speed
If oxide semiconductor pattern is used to increase electron mobility, then electron mobility is improved, but turn-off voltage increases over time due to blue light reactivity
Solution Approach 1:
The second oxide semiconductor layer with higher band gap is formed in advance as a protective barrier before the oxide semiconductor pattern is exposed to blue light during operation. This preliminary protective structure prevents blue light from reaching and degrading the main channel layer, thereby maintaining stable turn-off voltage characteristics.
Solution Approach 2:
Different regions of the oxide semiconductor structure have different compositions optimized for different functions: the first layer (In-Ga-Zn-O) is optimized for high electron mobility in the channel region, while the second layer (In-Zn-O with higher band gap) is optimized for light blocking and stability. Each layer has localized properties tailored to its specific function.
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 reduces the absolute value of turn-off voltage and prevents current leakage, improving the operating characteristics and longevity of TFTs in display devices by blocking blue light and maintaining low power consumption.
Implementation Method 1
the first oxide semiconductor layer has a higher band gap to prevent blue light incidence and reduce leakage current
Data Source
AI summary
A display substrate is provided. The display substrate includes a gate interconnection disposed on an insulating substrate, an oxide semiconductor pattern disposed on the gate interconnection and including an oxide semiconductor, and a data interconnection disposed on the oxide semiconductor pattern to interconnect the gate interconnection. The oxide semiconductor pattern includes a first oxide semiconductor pattern having a first oxide and a first element and a second oxide semiconductor pattern having a second oxide.