Crystalline Indium Oxide TFT Selective Etching
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Solution Overview
Problem
Existing thin film transistors using silicon-based semiconductor films face challenges with low switching speed for high-speed image display, energy-intensive crystallization processes, and instability when exposed to electric current, while indium oxide-based films suffer from oxygen deficiency and non-selective etching issues.
Innovation Solution
A thin film transistor with a crystalline indium oxide semiconductor film containing a positive trivalent metal oxide, such as boron, aluminum, or gallium oxide, is developed, allowing for selective etching of a thin metal film and reducing carrier density to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent semiconductor film composed of indium oxide, gallium oxide and zinc oxide, or zinc oxide and magnesium oxide is used, then light transmittance is improved and stability is enhanced, but the film cannot be selectively etched with thin metal films because it is etched simultaneously with the metal film
Solution Approach 1:
The invention changes the compositional parameters of the transparent semiconductor film by incorporating specific metal oxides (In2O3, Ga2O3, ZnO, MgO) in controlled ratios, and adjusts the crystalline structure parameters to achieve a material that resists etching by weak acids while maintaining transparency and stability
Solution Approach 2:
The invention creates a composite transparent semiconductor film by combining multiple metal oxides (indium oxide, gallium oxide, zinc oxide, magnesium oxide) with specific properties, achieving a material that simultaneously provides high transparency, excellent stability, and resistance to weak acid etchants, thus enabling selective etching of thin metal films
2Quantity of substance
If a polycrystalline indium oxide film is used, then carrier density can be reduced, but oxygen deficiency is generated making it difficult to achieve carrier density of 2×10^17 cm^-3
Solution Approach 1:
The invention introduces oxygen during the film formation process as an intermediary substance that prevents oxygen deficiency in the polycrystalline indium oxide film, enabling the achievement of low carrier density (2×10^17 cm^-3 or lower) while maintaining structural integrity and stability
Solution Approach 2:
The invention changes the oxygen partial pressure parameter during film formation to an optimized range (3×10^-3 to 1 atm), which controls the oxygen content in the polycrystalline indium oxide film, preventing oxygen deficiency and enabling precise control of carrier density
3Speed
If crystalline silicon-based thin film is used, then switching speed is improved, but heating at 800°C or higher or laser heating is necessary requiring large energy or many production steps
Solution Approach 1:
The invention changes the crystallization temperature parameter from conventional high temperatures (800°C or higher) to a lower temperature range (400-600°C), achieving crystalline structure formation in indium oxide-based semiconductor film that provides high switching speed while significantly reducing energy consumption and simplifying production steps
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 enables high-performance thin film transistors with improved switching speed, reduced energy requirements, and stable operation by controlling carrier density and preventing oxygen deficiency, while allowing selective etching of the metal film.
Implementation Method 1
a semiconductor film which is composed mainly of indium oxide and contains a positive trivalent metal oxide
Implementation Method 2
a crystalline indium oxide semiconductor film which is composed mainly of indium oxide
Data Source
AI summary
To provide a thin film transistor having an indium oxide-based semiconductor film which allows only a thin metal film on the semiconductor film to be selectively etched. A thin film transistor having a crystalline indium oxide semiconductor film which is composed mainly of indium oxide and contains a positive trivalent metal oxide.