Oxide Semiconductor Non-Linear Element for Display Protection
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Solution Overview
Problem
Existing display devices using oxide semiconductors face challenges in achieving stable operation and enhanced protective circuit functionality, particularly due to the limitations of metal wirings in oxide semiconductor-based thin film transistors, which can lead to instability and reduced reliability.
Innovation Solution
A display device structure incorporating a non-linear element with a combination of oxide semiconductors of different oxygen contents, where the first oxide semiconductor layer with higher oxygen concentration has lower electrical conductivity and an amorphous structure, and the second oxide semiconductor layer with lower oxygen concentration has higher conductivity and nanocrystalline structure, is used to form a protective circuit. This configuration enhances the stability and functionality of the protective circuit by providing a stable connection between the oxide semiconductor layers and wiring layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal wirings are used in oxide semiconductor-based thin film transistors, then electrical conductivity is improved, but stability and reliability deteriorate due to junction leakage
Solution Approach 1:
The patent introduces an oxide semiconductor layer as an intermediary material between the metal wiring and the oxide semiconductor transistor. This intermediary layer mediates the electrical connection while preventing direct contact between metal and oxide semiconductor, thereby eliminating junction leakage and stabilizing the protective circuit's operation.
Solution Approach 2:
The patent changes the material parameter of the wiring layer from metal to oxide semiconductor. This parameter change fundamentally alters the electrical characteristics at the junction interface, eliminating the harmful junction leakage effect that occurs with metal wirings and improving overall reliability.
2Device complexity
If a simple wiring structure is used, then device complexity is reduced, but protective circuit functionality is insufficient
Solution Approach 1:
The oxide semiconductor wiring layer serves multiple functions simultaneously: it provides electrical connection like a traditional wiring layer, acts as a barrier to prevent junction leakage, and functions as part of the protective circuit structure. This multi-functionality allows the simple structure to achieve enhanced protective circuit functionality.
3Reliability
If oxide semiconductor layers with different oxygen contents are combined, then stability is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent utilizes parameter changes in oxygen content during the sputtering process to create different oxide semiconductor layers. By adjusting the oxygen partial pressure during deposition, the manufacturing process creates layers with different electrical characteristics, achieving stable operation without requiring complex additional processing steps.
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 proposed structure stabilizes the operation of the protective circuit and enhances its functionality by reducing junction leakage and improving the characteristics of the non-linear element, allowing for effective discharge of surge voltages and preventing electrostatic breakdown, thereby increasing the reliability of the display device.
Implementation Method 1
the first oxide semiconductor layer with higher oxygen concentration has lower electrical conductivity and an amorphous structure, and the second oxide semiconductor layer with lower oxygen concentration has higher conductivity and nanocrystalline structure
Data Source
AI summary
A protective circuit includes a non-linear element, which further includes a gate electrode, a gate insulating layer covering the gate electrode, a pair of first and second wiring layers whose end portions overlap with the gate electrode over the gate insulating layer and in which a conductive layer and a second oxide semiconductor layer are stacked, and a first oxide semiconductor layer which overlaps with at least the gate electrode and which is in contact with side face portions of the gate insulating layer and the conductive layer of the first wiring layer and the second wiring layer and a side face portion and a top face portion of the second oxide semiconductor layer. Over the gate insulating layer, oxide semiconductor layers with different properties are bonded to each other, whereby stable operation can be performed as compared with Schottky junction. Thus, the junction leakage can be decreased and the characteristics of the non-linear element can be improved.