Oxide Semiconductor Protective Circuit for Low-Leakage Displays
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Solution Overview
Problem
Existing display devices using oxide semiconductors face challenges in ensuring the reliability and stability of the protective circuit, particularly in maintaining operation stability and preventing electrostatic breakdown.
Innovation Solution
A display device is designed with a protective circuit formed using a non-linear element that includes a combination of oxide semiconductors with different oxygen contents, enhancing the function and stability of the protective circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective circuit is formed using conventional materials and structures, then the manufacturing process is simple, but the operational stability and reliability are insufficient
Solution Approach 1:
The patent applies parameter changes by utilizing oxide semiconductors with different oxygen contents to create non-linear elements with distinct electrical characteristics. The first oxide semiconductor layer has higher oxygen content for stability, while the second layer has lower oxygen content for conductivity, creating a non-linear I-V characteristic that enables protective circuit functionality without complex structures
Solution Approach 2:
The patent employs composite materials by combining oxide semiconductor layers with different oxygen stoichiometries (In-Ga-Zn-O with varying O content) to form a non-linear element. This composite structure integrates the stability of oxygen-rich regions with the conductivity of oxygen-deficient regions, achieving both reliability and functional performance in the protective circuit
2Reliability
If oxide semiconductors are used in the protective circuit, then operational stability is improved, but the device structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the oxide semiconductor into two distinct layers with different oxygen contents. The first layer (higher oxygen content) provides stability and forms the channel region, while the second layer (lower oxygen content) provides conductivity and forms the source/drain regions. This segmentation allows each layer to perform its specific function optimally
Solution Approach 2:
The patent implements local quality by creating regions with different oxygen concentrations within the oxide semiconductor structure. The channel formation region has higher oxygen content for stability, while the source and drain regions have lower oxygen content for higher conductivity. This local variation in material quality enables the protective circuit to achieve both stability and functionality without increasing overall structural complexity
3Reliability
If a non-linear element with multiple oxide semiconductor layers is used, then junction leakage is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies parameter changes by controlling the oxygen content during the formation of different oxide semiconductor layers. The first layer is formed with higher oxygen content to reduce junction leakage at the interface, while the second layer has lower oxygen content for conductivity. This parameter control is achieved through adjusted sputtering conditions or annealing processes
Solution Approach 2:
The patent applies preliminary action by forming the oxide semiconductor layers with controlled oxygen content before subsequent processing steps. The oxygen gradient is established in advance during film deposition, which prevents junction leakage issues that would otherwise require additional corrective processing steps later in the manufacturing sequence
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 non-linear element with oxide semiconductors of varying oxygen content improves the operational stability and reliability of the display device by reducing junction leakage and enhancing the thermal stability of the protective circuit.
Implementation Method 1
The non-linear element includes a combination of oxide semiconductors with different oxygen contents
Implementation Method 2
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
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.