Display Protective Circuit With Layered Oxide Semiconductors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thin film transistors using amorphous silicon have low field effect mobility, while those using polycrystalline silicon require costly crystallization steps and are not suitable for large glass substrates, and there is a need for improved protective circuits in display devices using oxide semiconductors to enhance reliability and stability.
Innovation Solution
A display device structure incorporating a protective circuit with a non-linear element formed from oxide semiconductors of varying oxygen content, including a first oxide semiconductor layer with higher oxygen concentration and a second layer with lower oxygen concentration, stacked with conductive layers, to stabilize operation and enhance functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If amorphous silicon is used for thin film transistor, then larger area substrate can be covered, but field effect mobility is low
Solution Approach 1:
The patent changes the material parameter from conventional silicon to oxide semiconductor, which enables high field effect mobility while maintaining compatibility with large area substrates. The oxide semiconductor layer is formed with specific oxygen content control to achieve the desired electrical characteristics for high mobility operation.
Solution Approach 2:
The patent employs a composite structure combining oxide semiconductor layer with insulating layers and conductive layers. The oxide semiconductor is stacked with gate insulating layers and channel protective layers to create a composite thin film transistor structure that achieves both high mobility and large area coverage.
2Speed
If polycrystalline silicon is used for thin film transistor, then field effect mobility is high, but crystallization step is required which increases process complexity
Solution Approach 1:
The patent changes the material parameter from polycrystalline silicon to oxide semiconductor, which achieves high field effect mobility without requiring crystallization steps. The oxide semiconductor can be formed directly in an amorphous state and then activated through simpler processes, eliminating the need for laser annealing or other crystallization techniques.
Solution Approach 2:
The patent extracts and removes the crystallization step from the manufacturing process by using oxide semiconductor material. This eliminates the need for laser annealing equipment and complex crystallization control, simplifying the overall manufacturing process while maintaining high mobility characteristics.
3Temperature
If oxide semiconductor is used for protective circuit, then manufacturing temperature can be reduced, but circuit reliability needs to be enhanced
Solution Approach 1:
The patent employs a composite structure with multiple oxide semiconductor layers having different oxygen contents. The first oxide semiconductor layer with higher oxygen content provides stability and reliability, while the second layer with lower oxygen content enables low-temperature processing. This composite approach achieves both low manufacturing temperature and high circuit reliability.
Solution Approach 2:
The patent applies local quality by creating regions with different oxygen concentrations within the oxide semiconductor structure. The first oxide semiconductor layer has higher oxygen content for stability and reliability, while the second layer has lower oxygen content for low-temperature processing compatibility. This spatial variation in material quality enables simultaneous achievement of both objectives.
Data Source
AI summary
A protective circuit includes a non-linear element which includes a gate electrode, a gate insulating layer covering the gate electrode, a first oxide semiconductor layer overlapping with the gate electrode over the gate insulating layer, a channel protective layer overlapping with a channel formation region of the first oxide semiconductor layer, and a pair of a first wiring layer and a second wiring layer whose end portions overlap with the gate electrode over the channel protective layer and in which a conductive layer and a second oxide semiconductor layer are stacked. 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 reduced and the characteristics of the non-linear element can be improved.