Hydrogen Capturing Layer for Oxide TFT Stability
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Solution Overview
Problem
The reliability of organic light emitting display devices is compromised due to threshold voltage shifts caused by changes in oxide properties, particularly due to residual hydrogen, which can lead to visible stains or luminance deviations on the screen, limiting the use of oxide thin film transistors in driving these devices.
Innovation Solution
Incorporating a hydrogen capturing material, such as a metal foil alloy with a hydrogen capturing metal, between the substrates to capture residual hydrogen and prevent its diffusion into the oxide thin film transistor, thereby stabilizing the threshold voltage and improving display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide thin film transistor is used to drive organic light emitting display device, then device can be manufactured with lighter weight and thinner profile, but threshold voltage shift occurs due to residual hydrogen diffusion into oxide semiconductor, causing reliability degradation and visible display defects
Solution Approach 1:
A hydrogen capturing layer is introduced as an intermediary component between the oxide semiconductor transistor and the encapsulation structure. This layer acts as a mediator that selectively captures residual hydrogen atoms, preventing them from diffusing into the oxide semiconductor and causing threshold voltage shifts. The hydrogen capturing layer thus protects the transistor while maintaining the device's lightweight and thin characteristics.
Solution Approach 2:
The invention converts the harmful effect of residual hydrogen (which causes threshold voltage instability) into a beneficial outcome by introducing a dedicated hydrogen capturing layer. This layer specifically targets and captures the harmful hydrogen atoms, transforming them from a reliability-degrading factor into a controlled element that can be managed through material selection and structural design, ultimately improving device reliability.
2Ease of manufacture
If residual hydrogen is present in the device structure, then manufacturing process is simplified, but hydrogen diffusion into oxide semiconductor causes threshold voltage shift and display quality degradation
Solution Approach 1:
The hydrogen capturing layer serves as an intermediary that addresses the conflict between manufacturing simplicity and precision. It allows the manufacturing process to remain relatively simple while introducing a functional layer that actively manages hydrogen, thereby achieving both ease of manufacture and precise threshold voltage control through the capturing layer's selective hydrogen absorption properties.
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 use of a hydrogen capturing material effectively reduces the impact of residual hydrogen on the oxide thin film transistor, enhancing the reliability and performance of the organic light emitting display device by preventing threshold voltage shifts and maintaining image quality.
Implementation Method 1
a hydrogen capturing material between the substrates to capture residual hydrogen
Data Source
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AI summary
An organic light emitting device (200) and a method of fabricating the same includes a first substrate (210); a thin film transistor (TFT, 220) on the first substrate; a planarization layer on the TFT; an organic light emitting diode (OLED, 230) on the planarization layer; a passivation layer on the OLED (240); a second substrate (260) on the passivation; and a hydrogen capturing material between the first and the second substrates to prevent oxidation of materials forming the TFT.