OLED Interlayer Insulating Stack for Hydrogen Blocking in Oxide TFTs
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Solution Overview
Problem
Display devices, particularly OLEDs, face challenges in preventing short circuits due to excessive hydrogen ions flowing into semiconductor channels, which can lower threshold voltages and cause defects in switching characteristics.
Innovation Solution
The implementation of a first interlayer insulating layer made of silicon nitride with controlled hydrogen release characteristics, formed by adjusting the ratios of ammonia, nitrogen, and silane, is used to reduce hydrogen inflow into semiconductor layers, thereby preventing short circuits and maintaining stable threshold voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional interlayer insulating layer is used, then the device structure is simple, but hydrogen ions flow into semiconductor channels causing short circuits and threshold voltage instability
Solution Approach 1:
The interlayer insulating layer is divided into multiple sub-layers with different materials and functions. The first interlayer insulating layer (silicon nitride) is positioned closer to the semiconductor layer to block hydrogen, while the second interlayer insulating layer (silicon oxide) is positioned farther away. This segmentation allows each layer to perform its specific function optimally, preventing hydrogen ion diffusion while maintaining structural organization.
Solution Approach 2:
The patent uses a composite interlayer insulating layer structure combining silicon nitride and silicon oxide materials. This composite approach leverages the hydrogen-blocking properties of silicon nitride and the insulating properties of silicon oxide, creating a more effective barrier against hydrogen ion diffusion than either material could provide alone.
2Reliability
If the interlayer insulating layer releases excessive hydrogen, then the manufacturing process is simple, but semiconductor channels experience short circuits due to hydrogen ion influx
Solution Approach 1:
The patent modifies the composition parameters of the silicon nitride layer by controlling the ammonia to silane ratio during deposition. By optimizing this parameter ratio, the layer achieves reduced hydrogen content and improved hydrogen-blocking performance without requiring complex additional manufacturing steps.
3Reliability
If the first interlayer insulating layer is positioned closer to the semiconductor layer, then hydrogen blocking is improved, but the device structure becomes more complex
Solution Approach 1:
The interlayer insulating layer is divided into multiple sub-layers with different materials and functions. The first interlayer insulating layer (silicon nitride) is positioned closer to the semiconductor layer to block hydrogen, while the second interlayer insulating layer (silicon oxide) is positioned farther away. This segmentation allows each layer to perform its specific function optimally, preventing hydrogen ion diffusion while maintaining structural organization.
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 approach effectively reduces hydrogen ion flow into semiconductor channels, preventing short circuits and ensuring stable switching characteristics in OLED display devices by adjusting the hydrogen release characteristics of the interlayer insulating layer.
Implementation Method 1
the material of the first interlayer insulating layer and the material of the second interlayer insulating layer are different from each other... The first interlayer insulating layer may comprise nitrogen, hydrogen, and silicon, wherein the nitrogen and hydrogen are combined through a first bond, the silicon and the hydrogen are combined through a second bond, and a ratio of the first bond to the second bond is in a range of about 15 to about 30... A release amount (intensity (A)) of the hydrogen of the first interlayer insulating layer may be at most about 2.0E-09 at a temperature of at least about 350° C.
Data Source
AI summary
A display device includes a base substrate including a display area and a non-display area around the display area are defined, a first interlayer insulating layer disposed on the base substrate, a second interlayer insulating layer disposed on the first interlayer insulating layer, a first semiconductor layer disposed on the second interlayer insulating layer and including an oxide, and a first gate insulating layer disposed on the first semiconductor layer, wherein the material of the first interlayer insulating layer and the material of the second interlayer insulating layer are different from each other. Methods of manufacturing a display device are also disclosed.