Oxide TFT Oxygen Supplementation Layer for Stable Switching
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Solution Overview
Problem
Conventional metal oxide thin film transistors (TFTs) suffer from poor switching properties due to defects on the side of the active layer away from the substrate, which are exacerbated by etchant effects during source and drain electrode formation, leading to unstable threshold voltage and biased temperature stress, affecting their performance in display applications.
Innovation Solution
Incorporating an oxygen supplementation layer containing metal oxides, which overlaps with the active layer but not the source and drain electrodes, to diffuse oxygen and reduce oxygen vacancies, thereby enhancing the stability and switching properties of the TFTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If source and drain electrodes are formed by etching metal material with etchant, then the electrodes can be manufactured, but defects are generated on the active layer especially on the side away from the substrate
Solution Approach 1:
The patent converts the harmful effect of the etchant by introducing an oxygen supplementation layer that transforms the etchant's interaction with the active layer. The oxygen in the supplementation layer reacts with the etchant, preventing direct damage to the active layer while allowing the etching process to proceed for source and drain electrode formation.
Solution Approach 2:
The oxygen supplementation layer acts as an intermediary between the etchant and the active layer. It is positioned between them to mediate their interaction, protecting the active layer from direct etchant exposure while still allowing the etching process to function for electrode formation.
2Reliability
If oxygen supplementation layer is added to reduce defects, then switching properties are improved, but device structure becomes more complex
Solution Approach 1:
The oxygen supplementation layer is merged with the insulating layer structure. The supplementation layer is formed between the insulating layer and the active layer, combining multiple functions into a integrated structure that provides both insulation and oxygen supplementation without requiring completely separate components.
Solution Approach 2:
The oxygen supplementation layer serves multiple functions simultaneously: it provides oxygen to prevent defects during etching, acts as part of the insulating structure, and contributes to the overall device performance. This multi-functionality reduces the need for additional separate components.
3Reliability
If oxygen supplementation layer covers the entire active layer, then all defects are reduced, but source and drain electrode formation is affected
Solution Approach 1:
The oxygen supplementation layer is positioned locally rather than uniformly covering the entire active layer. It is specifically placed in regions where defect prevention is most critical, such as beneath the channel region, while allowing the etching process to access the source and drain electrode areas where the layer is absent or reduced.
Solution Approach 2:
The oxygen supplementation layer is segmented into different regions with varying thickness or presence. It is concentrated in areas requiring protection from etchant damage while being reduced or absent in areas where electrode formation is prioritized, creating a spatially differentiated structure.
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 oxygen supplementation layer improves the stability of the TFTs by reducing defects and enhancing the mobility and subthreshold swing, resulting in better performance and reliability for display devices.
Implementation Method 1
oxygen introduced in forming the oxygen supplementation layer can diffuse to the active layer, so that a defect in the active layer can be reduced
Data Source
AI summary
Provided is a thin film transistor and a method for manufacturing thereof, a display panel, and a display device, which relates to the field of display technologies. The thin film transistor includes an active layer, source and drain electrodes, and an oxygen supplementation layer. As an orthogonal projection of the oxygen supplementation layer on the base substrate is at least partially overlapped with an orthogonal projection of a target portion of the active layer on the base substrate, oxygen introduced in forming the oxygen supplementation layer in the thin film transistor is capable of diffusing to the target portion of the active layer, such that a defect in the target portion of the active layer is reduced, and a property of the thin film transistor is greater.