Amorphous Oxide Layer Formation for Flexible Transistors
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Solution Overview
Problem
The manufacture of field effect transistors using silicon thin-films on resin substrates is challenging due to the high temperature thermal processes required, which are difficult to achieve on resin substrates with low thermal resistance, and zinc oxide (ZnO) materials primarily form in a polycrystalline phase, leading to scattered carriers and reduced electron mobility.
Innovation Solution
A method for manufacturing field effect transistors involving deposition of an amorphous oxide layer on a substrate, where pre- and post-treatment processes include ultraviolet irradiation, plasma treatment, and thermal processing in oxygen-containing atmospheres, and the use of deposition techniques like resistance heating, electron beam deposition, or chemical vapor deposition at a substrate temperature of 70°C or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon thin-film transistor is manufactured using conventional thermal processes, then high electron mobility can be achieved, but the process requires high temperature which cannot be applied to resin substrates with low thermal resistance
Solution Approach 1:
The patent changes the material parameter from silicon to oxide semiconductor (In-Ga-Zn-O), which enables low-temperature processing while maintaining transistor functionality. This material substitution allows deposition at temperatures suitable for resin substrates while achieving the desired electron mobility through controlled amorphous phase formation and oxygen deficiency reduction
Solution Approach 2:
The patent replaces conventional thermal processing with deposition techniques (resistance heating deposition, electron beam deposition, chemical vapor deposition) that can form amorphous oxide layers at lower temperatures. This substitution of processing methodology enables compatibility with low-thermal-resistance resin substrates
2Temperature
If ZnO is used as the oxide semiconductor material, then low temperature deposition is enabled, but the material forms in a polycrystalline phase causing carrier scattering and reduced electron mobility
Solution Approach 1:
The patent changes the phase parameter of the oxide semiconductor from polycrystalline to amorphous by controlling deposition conditions and using specific deposition techniques. This phase change eliminates grain boundaries and carrier scattering at particle interfaces, thereby improving electron mobility while maintaining low deposition temperature
Solution Approach 2:
The patent uses a composite approach by forming an amorphous oxide layer containing In-Ga-Zn-O and controlling its oxygen deficiency. The specific composition and amorphous structure create a material that combines low-temperature processability with high electron mobility, overcoming the limitations of pure polycrystalline ZnO
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 method enables the production of field effect transistors with improved electron mobility and reduced oxygen deficiency, enhancing the stability and performance of the transistors, particularly on flexible substrates, by forming a stable amorphous oxide layer with controlled electron carrier density.
Implementation Method 1
a step of irradiating ultraviolet rays onto the substrate surface in an ozone atmosphere
Implementation Method 2
a step of irradiating plasma onto the substrate surface
Implementation Method 3
a step of irradiating oxygen-containing plasma onto the substrate comprising the active layer
Implementation Method 4
a step of thermal processing at a higher temperature than the deposition temperature of the active layer in the second step
Implementation Method 5
resistance heating deposition
Implementation Method 6
electron beam deposition
Implementation Method 7
chemical vapor deposition
Data Source
AI summary
Provided is a novel method for manufacturing a field effect transistor. Prior to forming an amorphous oxide layer on a substrate, ultraviolet rays are irradiated onto the substrate surface in an ozone atmosphere, plasma is irradiated onto the substrate surface, or the substrate surface is cleaned by a chemical solution containing hydrogen peroxide.