Oxide Display Transistor Stack for Oxygen Vacancy Control
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Solution Overview
Problem
Oxide semiconductor-based light emitting display devices face issues due to oxygen defects in the semiconductor layer, which cause them to operate more like conductors, leading to reliability problems and limited driving range in low gray levels.
Innovation Solution
A display device structure featuring a first semiconductor layer and a dummy semiconductor layer of the same material, with a second semiconductor layer of different material, where the dummy layer supplies oxygen to the second semiconductor layer to mitigate oxygen vacancies, and a manufacturing method that includes forming and patterning these layers to ensure proper overlap and thickness for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If oxide semiconductor is used as semiconductor layer, then low power consumption and high luminance are achieved, but oxygen defects cause conductor-like operation and reliability issues
Solution Approach 1:
The patent changes the material parameter by introducing a dual-layer semiconductor structure with different compositions (first layer: In-Ga-Zn-O with In:(Ga+Zn) ratio of 0.2-0.8; second layer: In-Ti-Ga-Zn-O with In:(Ti+Ga+Zn) ratio of 0.3-0.7). This compositional parameter change reduces oxygen defects and prevents conductor-like operation while maintaining low power consumption characteristics
Solution Approach 2:
The patent employs a composite semiconductor structure where two different oxide semiconductor materials are stacked. The first oxide semiconductor layer (In-Ga-Zn-O) and second oxide semiconductor layer (In-Ti-Ga-Zn-O) form a composite material system that combines the advantages of both materials, achieving both low power consumption and high reliability by suppressing oxygen vacancy formation
2Illumination intensity
If oxide semiconductor is used as semiconductor layer, then high luminance is achieved, but oxygen defects cause conductor-like operation and limited driving range in low gray levels
Solution Approach 1:
The patent modifies the compositional parameters of the semiconductor layers to control oxygen defect density. By optimizing the metal ratios (In:(Ga+Zn) = 0.2-0.8 for first layer, In:(Ti+Ga+Zn) = 0.3-0.7 for second layer), the material maintains high luminance capability while preventing excessive carrier generation from oxygen defects that would limit low gray level driving range
3Reliability
If multiple semiconductor layers with different materials are used, then oxygen defects are mitigated and reliability is improved, but device structure becomes more complex
Solution Approach 1:
The patent segments the semiconductor layer into two distinct functional layers: a first oxide semiconductor layer (In-Ga-Zn-O) and a second oxide semiconductor layer (In-Ti-Ga-Zn-O). Each layer has optimized composition ratios that contribute to oxygen defect mitigation, achieving high reliability through functional segmentation rather than a single complex material
Solution Approach 2:
The patent merges two oxide semiconductor materials with complementary properties into a stacked structure. The first layer (In-Ga-Zn-O) and second layer (In-Ti-Ga-Zn-O) are combined vertically, where each layer contributes to oxygen defect suppression, achieving enhanced reliability through material combination while maintaining a relatively simple fabrication process
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 enhances the reliability of transistors, improves the driving range in low gray levels, and simplifies the manufacturing process by reducing the number of masks used, effectively addressing the oxygen defect issues and improving the overall performance of the oxide semiconductor elements.
Implementation Method 1
the dummy layer supplies oxygen to the second semiconductor layer to mitigate oxygen vacancies
Data Source
AI summary
A display device includes: a substrate; a first semiconductor layer and a dummy semiconductor layer on the same layer on a surface of the substrate and comprising the same material as each other; a second semiconductor layer overlapping the dummy semiconductor layer in a direction perpendicular to the surface of the substrate, the first semiconductor layer and the second semiconductor layer comprising different materials from each other; a first transistor comprising the first semiconductor layer, a first source electrode, and a first drain electrode, the first source electrode and the first drain electrode being connected to the first semiconductor layer; a second transistor comprising the second semiconductor layer, a second source electrode, and a second drain electrode, the second source electrode and the second drain electrode being connected to the second semiconductor layer; and a light- emitting element connected to the first transistor.