Layered Electrode Structure for Low Resistance in Display Apparatus
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Solution Overview
Problem
Display apparatuses face challenges in achieving high resistance for gate electrodes of thin film transistors and storage capacitors, which affects the quality and reliability of high-resolution displays.
Innovation Solution
The display apparatus incorporates a substrate with thin film transistors and storage capacitors, where the gate electrodes and storage capacitor electrodes are designed with specific layered structures using aluminum alloys and tantalum, with carefully controlled thicknesses and compositions to enhance resistance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the upper layer of the storage capacitor electrode is increased to reduce resistance, then the resistance decreases, but the area occupied by the electrode increases
Solution Approach 1:
The patent changes the thickness parameter of the upper layer of the storage capacitor electrode from a standard uniform thickness to a specifically increased thickness (second thickness greater than first thickness), which directly reduces the resistance of the electrode while maintaining the same planar area footprint
Solution Approach 2:
The storage capacitor electrode is constructed as a composite structure with two distinct layers: a first layer with thickness of first thickness and a second layer with thickness of second thickness. This composite structure allows optimization of electrical properties (lower resistance through increased second layer thickness) without increasing the planar area
2Reliability
If the thickness of the gate electrode upper layer is increased to reduce resistance, then the resistance decreases, but the manufacturing complexity increases
Solution Approach 1:
The patent modifies the thickness parameter of the gate electrode's upper layer (third thickness greater than fourth thickness) to reduce resistance. This parameter change is implemented within the existing multi-layer electrode structure, avoiding fundamental process redesign
Solution Approach 2:
The gate electrode is divided into a lower layer (fourth thickness) and an upper layer (third thickness), allowing independent optimization of each layer's thickness to achieve low resistance while maintaining compatibility with standard manufacturing processes
3Reliability
If aluminum alloy with low atomic percentage of first element is used, then the resistance is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a precise parameter range for the atomic percentage of the first element in the aluminum alloy (0.01 at% to 0.1 at%), optimizing the resistance properties while establishing clear manufacturing control targets
Solution Approach 2:
The patent applies different material compositions to different parts of the electrode structure: the lower layers use aluminum alloy with controlled first element content, while the upper layers use the same aluminum alloy but with different thicknesses, creating local optimization of electrical properties
Data Source
AI summary
A display apparatus includes a thin film transistor on the substrate, the thin film transistor including a first semiconductor layer and a first gate electrode overlapping the first semiconductor layer wherein a first gate insulating layer is disposed between the first semiconductor layer and the first gate electrode, and a storage capacitor including a lower electrode including a first lower layer and a first upper layer stacked each other and an upper electrode including a second lower layer and a second upper layer stacked each other, wherein the upper electrode overlaps the lower electrode, and a second gate insulating layer is disposed between the upper electrode and the lower electrode, a display element electrically connected to the thin film transistor, wherein the second upper layer has a thickness greater than a thickness of the first upper layer.