Oxide Semiconductor TFT With Segmented Channel Strips
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Solution Overview
Problem
Oxide semiconductor TFTs face challenges in stability and power consumption, especially when subjected to external stress and oxygen vacancies, making them less suitable for flexible display devices.
Innovation Solution
The TFT design includes a flexible substrate with an IGZO oxide semiconductor layer and a silicon oxide barrier layer, where the channel region is divided into multiple strips, and fluorine ions occupy oxygen vacancies at the interface, reducing power consumption and improving stability by lowering contact and channel resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If oxide semiconductor TFT is used in flexible display devices, then the device can achieve flexibility and thinness, but the TFT stability deteriorates due to external stress during winding causing changes in PBTS and SS
Solution Approach 1:
The channel region is divided into multiple channel strips spaced apart from each other. This segmentation reduces the overall channel width subjected to stress during winding, thereby maintaining TFT stability while preserving flexibility. The spaced channel strips experience reduced external stress compared to a continuous channel structure.
Solution Approach 2:
A barrier layer is introduced specifically in the channel region to address the local issue of oxygen vacancies. The barrier layer is positioned only where needed (in the channel region) to reduce oxygen vacancies and electronic defects, improving local material quality without affecting other regions of the device.
2Ease of manufacture
If oxide semiconductor material is used, then the manufacturing process is simpler and compatibility with a-Si TFT is improved, but device stability deteriorates due to large number of oxygen vacancies causing large electronic defects
Solution Approach 1:
The barrier layer is selectively positioned in the channel region to address the local problem of oxygen vacancies. This localized approach improves material quality where it is most needed (in the channel) while maintaining the overall simplicity of the oxide semiconductor manufacturing process.
Solution Approach 2:
The device structure combines oxide semiconductor material with a barrier layer to create a composite structure. This composite approach leverages the manufacturing advantages of oxide semiconductors while adding the stabilizing properties of the barrier layer to reduce oxygen vacancies and electronic defects.
3Loss of energy
If the channel region is divided into spaced channel strips, then power consumption is reduced and stability in winding state is improved, but device structure becomes more complex
Solution Approach 1:
The channel region is segmented into multiple spaced channel strips, which reduces the total channel width and thereby reduces power consumption. The segmentation also improves stability in winding state by reducing stress on the channel. While this increases structural complexity, the benefits in energy efficiency and reliability outweigh the added complexity.
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 reduces power consumption and enhances the stability of the TFT in a winding state, enabling its application in bendable devices by maintaining consistent current-voltage curves and threshold voltages between winding and non-winding states.
Implementation Method 1
The interface between the channel region and the barrier layer comprises fluoride ions that occupy oxygen vacancies in the channel region
Data Source
AI summary
The invention provides an oxide semiconductor TFT and manufacturing method thereof. The oxide semiconductor TFT comprises: a substrate, a gate on the substrate, a gate insulating layer on the gate and substrate, an oxide semiconductor layer on the gate insulating layer, and a barrier layer on the semiconductor layer, and a source and a drain on the oxide semiconductor layer and gate insulating layer; the oxide semiconductor layer comprising: a channel region and two contact regions respectively located at two sides of the channel region, and the barrier layer being located on the channel region; the channel region comprising a plurality of channel strips spaced apart in a channel width direction, and the barrier layer comprising a plurality of barrier strips respectively corresponding to the plurality of channel strips. The invention can reduce power consumption of the oxide semiconductor TFT and improve and the stability in the winding state.