InGaZnO Oxide Semiconductor Composition for TFT Stability
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Solution Overview
Problem
The properties of oxide semiconductors used in thin film transistors (TFTs) vary with composition, leading to unstable electric properties and reduced process resistance, necessitating optimization for improved performance.
Innovation Solution
An oxide semiconductor comprising gallium (Ga), indium (In), zinc (Zn), and oxygen (O) with specific atomic composition ratios (0.01≦Zn/(In+Zn)≦0.22 and 0.25≦In/(In+Ga)≦0.60) is used to enhance electric properties and process resistance, and the composition is determined using techniques like Auger electron spectroscopy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide semiconductor composition is not optimized, then manufacturing flexibility is maintained, but electric properties stability deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the atomic composition ratios of In, Ga, and Zn in the oxide semiconductor to specific ranges (In: 30-70 at%, Ga: 5-65 at%, Zn: 5-65 at%). This compositional parameter optimization directly improves electric properties stability including carrier concentration and mobility, while maintaining manageable manufacturing complexity through defined composition ranges.
Solution Approach 2:
The patent employs composite materials by creating a multi-element oxide semiconductor system containing In-Ga-Zn-O. This composite structure combines the beneficial properties of individual elements: In for high carrier concentration, Ga for mobility enhancement, and Zn for structural stability. The synergistic combination achieves superior electric properties that single-element oxides cannot provide.
2Reliability
If oxide semiconductor composition varies, then material flexibility is maintained, but process resistance deteriorates
Solution Approach 1:
The patent uses parameter changes by establishing specific composition ranges for In, Ga, and Zn atoms in the oxide semiconductor. These controlled compositional parameters ensure consistent process resistance during manufacturing while avoiding the complexity of precise single-point composition control. The ranges provide manufacturing windows that balance reliability with ease of production.
3Reliability
If conventional silicon-type materials are used, then manufacturing experience is available, but electric properties enhancement is limited
Solution Approach 1:
The patent applies composite materials by developing an In-Ga-Zn-O oxide semiconductor that replaces conventional silicon-type channel layers. This composite oxide system achieves superior electric properties including higher carrier concentration (10^19-10^21 cm^-3) and mobility compared to silicon, while the sputtering-based manufacturing process maintains adaptability to existing production lines with modified deposition parameters.
Solution Approach 2:
The patent employs parameter changes by transitioning from silicon-type materials to oxide semiconductors with different physical and chemical parameters. The oxide semiconductor operates with different carrier concentration ranges, mobility characteristics, and deposition temperature windows, enabling electric properties enhancement while requiring adjustments in manufacturing parameters such as sputtering power, oxygen partial pressure, and substrate temperature.
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 composition achieves TFTs with improved electric properties and process resistance, resulting in enhanced display quality and productivity for various display devices.
Implementation Method 1
the composition is determined using techniques like Auger electron spectroscopy
Data Source
AI summary
The present invention provides an oxide semiconductor that realizes a TFT excellent in electric properties and process resistance, a TFT comprising a channel layer formed of the oxide semiconductor, and a display device equipped with the TFT. The oxide semiconductor of the present invention is an oxide semiconductor for a thin film transistor, wherein the oxide semiconductor contains Ga (gallium), In (indium), Zn (zinc), and O (oxygen) as constituent atoms, and the oxide semiconductor has Zn atomic composition satisfying the equation of 0.01≦Zn/(In+Zn)≦0.22.