Display TFT Layer Structure to Block Hydrogen Migration
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Solution Overview
Problem
Existing display apparatuses face challenges in maintaining optimal device characteristics of transistors due to hydrogen migration during manufacturing processes, particularly when using different semiconductor materials for thin-film transistors.
Innovation Solution
The display apparatus is designed with specific hole structures and heat-treatment processes to isolate and treat the first semiconductor layer before forming the second semiconductor layer, preventing hydrogen migration and maintaining the integrity of both transistor types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat-treatment process is applied to improve first thin-film transistor characteristics, then device characteristics of first TFT are improved, but hydrogen migrates to second semiconductor layer causing threshold voltage shifts
Solution Approach 1:
An oxide layer is introduced as an intermediary barrier between the first and second semiconductor layers. This oxide layer prevents hydrogen generated during heat-treatment of the first TFT from migrating to the second semiconductor layer, thereby resolving the contradiction between improving first TFT characteristics and preventing harmful hydrogen migration.
Solution Approach 2:
The harmful hydrogen is extracted or isolated from the system by containing it within the first semiconductor layer region through the oxide barrier. This prevents hydrogen from affecting the second semiconductor layer while allowing the heat-treatment process to proceed for improving first TFT characteristics.
2Reliability
If different semiconductor materials are used for first and second thin-film transistors, then optimized performance for each transistor type is achieved, but hydrogen migration occurs during manufacturing
Solution Approach 1:
The oxide layer serves as a protective intermediary that stabilizes the composition integrity of the second semiconductor layer by blocking hydrogen migration, while allowing the first and second TFTs to use different semiconductor materials for optimized performance.
Solution Approach 2:
Different semiconductor materials are used in different local regions (first TFT region vs. second TFT region) to optimize performance, while the oxide layer provides localized protection at the interface to maintain composition stability and prevent cross-contamination.
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 approach enhances the device characteristics of the first thin-film transistor while preserving the performance of the second thin-film transistor, improving overall display performance and reducing the risk of threshold voltage shifts.
Implementation Method 1
heat-treating the first semiconductor layer
Data Source
AI summary
Provided is a display apparatus including a substrate, a first thin-film transistor disposed over the substrate and including a first semiconductor layer and a first gate electrode, a second thin-film transistor including a second semiconductor layer and a second gate electrode, a first insulating layer between the first semiconductor layer and the first gate electrode, a second insulating layer between the first gate electrode and the second semiconductor layer, a third insulating layer between the second semiconductor layer and the second gate electrode, a fourth insulating layer on the second gate electrode, a first hole above the first semiconductor layer and passing through the first insulating layer and the second insulating layer, and a second hole within the first hole and passing through the third insulating layer and the fourth insulating layer.