Light-Shielding Layer for Oxide Semiconductor Stability
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Solution Overview
Problem
Oxide semiconductor-based thin-film transistors in organic light-emitting display apparatuses are susceptible to changes in threshold voltage and stability due to moisture and oxygen exposure, especially under DC bias, and existing barrier films like AlOx or TiN are difficult to apply to large substrates, limiting mass productivity.
Innovation Solution
An organic light-emitting display apparatus with a light-shielding layer formed by oxidizing a photosensitive high polymer pixel defining layer, which shields blue light and prevents external light from entering the active layer, thereby enhancing the stability of the oxide semiconductor and allowing for easier application to large substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a film formed of AlOx or TiN is used to reinforce the barrier feature against moisture or oxygen, then the stability of the oxide semiconductor is improved, but the ease of manufacture deteriorates because such film is difficult to apply to large substrates
Solution Approach 1:
The patent changes the material composition and formation method of the barrier film. Instead of using AlOx or TiN formed by reactive sputtering or ALD, the patent uses a silicon oxide-based insulating layer that can be formed by conventional PECVD or spin coating methods, making it suitable for large substrate manufacturing while maintaining barrier functionality
Solution Approach 2:
The patent employs a silicon oxide-based insulating layer that can be formed using simple, cost-effective processes like spin coating followed by thermal oxidation or PECVD, replacing the expensive and complex reactive sputtering or ALD processes required for AlOx or TiN films
2Reliability
If reactive sputtering or atomic layer deposition (ALD) is used to form the barrier film, then the barrier feature against moisture or oxygen is improved, but the productivity deteriorates because the film is difficult to apply to large substrates
Solution Approach 1:
The patent changes the formation process parameters from complex reactive sputtering or ALD to simpler PECVD or spin coating methods with thermal oxidation, enabling batch processing of large substrates and improving mass productivity while maintaining adequate barrier properties
Solution Approach 2:
The silicon oxide-based insulating layer serves multiple functions: it provides barrier protection against moisture and oxygen, acts as a gate insulating layer, and can be formed using conventional semiconductor manufacturing processes that are already optimized for mass production of large substrates
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 light-shielding layer effectively blocks blue light and external light, improving the stability of the oxide semiconductor and increasing mass productivity by preventing light-induced degradation and facilitating larger substrate applications.
Implementation Method 1
a light-shielding layer on a surface of the PDL to shield light incident to the active layer
Implementation Method 2
The light-shielding layer may be formed by oxidizing the surface of the PDL
Data Source
AI summary
An organic light-emitting display apparatus includes a light-shielding layer formed on a pixel defining layer to prevent external light or internal light from entering an active layer of a thin-film transistor (TFT), thus improving the stability of the active layer, and a method of manufacturing the organic light-emitting display apparatus.