Thin-Film Transistor Buffer Layers to Limit Hydrogen Outgassing
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Solution Overview
Problem
Conventional thin-film transistors face issues such as hydrogen pile-up and outgassing during dehydrogenation, leading to pixel defects, increased leakage current, and gate bias due to electron traps in the buffer layer, which affect the performance and reliability of display apparatuses.
Innovation Solution
The buffer layer in the thin-film transistor is designed with an inorganic insulating material, limiting the area ratio of N—H bonds to 0.5% or less, reducing hydrogen content and defects, and employing specific deposition processes to control N—H bond content and pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional buffer layers are used in thin-film transistors, then manufacturing is simpler, but hydrogen pile-up and outgassing occur during dehydrogenation causing pixel defects and increased leakage current
Solution Approach 1:
The patent changes the chemical composition parameters of the buffer layer by using inorganic insulating materials (silicon oxide, silicon nitride, silicon oxynitride) with controlled N-H bond content (0.5% or less), thereby reducing hydrogen outgassing while maintaining manufacturing simplicity
Solution Approach 2:
The patent employs composite inorganic insulating materials combining silicon oxide, silicon nitride, and silicon oxynitride in the buffer layer to achieve both low hydrogen content and good insulating properties, resolving the contradiction between reliability and harmful hydrogen outgassing
2Ease of manufacture
If buffer layer with higher N-H content is used, then manufacturing is easier, but defects increase and threshold voltage changes occur
Solution Approach 1:
The patent precisely controls the N-H bond content parameter in the buffer layer to 0.5% or less through optimized deposition processes, achieving both ease of manufacture and high manufacturing precision by establishing clear quality criteria
3Object-generated harmful factors
If inorganic insulating layer with low N-H content is used, then hydrogen outgassing is reduced, but manufacturing complexity increases due to deposition process control requirements
Solution Approach 1:
The patent simplifies process control by focusing on key parameters (power: 6-10 kW, pressure: 700-900 Torr, gas flow ratios) during deposition, making the complexity manageable through specific parameter ranges rather than requiring complex real-time adjustments
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 minimizes hydrogen outgassing and defects, reducing threshold voltage and gate bias, thereby improving image display quality and reducing momentary afterimages in display apparatuses.
Implementation Method 1
an amount of outgassing hydrogen, measured by thermal desorption spectroscopy (TDS) at a temperature of about 500° C. or higher, may be about 9×1015 ea/cm2 or less
Implementation Method 2
the forming the buffer layer may be performed by a deposition process, and a power applied for the deposition of the buffer layer may be about 6 KW to about 10 KW
Data Source
AI summary
Provided are a thin film transistor substrate which include a substrate, a buffer layer and a thin film transistor, a display apparatus including the thin film transistor substrate, and a method of manufacturing the display apparatus including the thin film transistor substrate. The buffer layer includes an inorganic insulating layer. An area ratio of a peak corresponding to an N—H bond in the buffer layer is 0.5% or less based on a total peak area in a Fourier transform infrared spectroscopy (FTIR).