Hybrid TFT Substrate with Polycrystalline and Oxide Semiconductors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thin film transistor substrates for flat panel displays face challenges in achieving low power consumption and efficient manufacturing with existing technologies, particularly in developing portable and wearable devices, where two transistors with different characteristics are needed on the same substrate.
Innovation Solution
A thin film transistor substrate is designed with a polycrystalline semiconductor material for driver ICs and an oxide semiconductor material for switching transistors, utilizing a top-gate structure for the polycrystalline semiconductor material and a bottom-gate structure for the oxide semiconductor material, with a hydrogenation process to stabilize the polycrystalline layer and thermal treatment to stabilize the oxide layer, ensuring efficient power management and low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a single type of thin film transistor is used on the substrate, then the manufacturing process is simple, but power consumption cannot be optimized for portable devices
Solution Approach 1:
The patent applies local quality by implementing different transistor types in different regions of the display device. Specifically, low-power transistors are used in peripheral driving circuits where power consumption is critical, while high-speed transistors are used in pixel regions where response speed is more important. This regional differentiation optimizes overall power consumption without compromising display performance.
Solution Approach 2:
The patent segments the transistor system into two distinct types: low-power transistors for driving circuits and high-speed transistors for pixel operations. This segmentation allows each transistor type to be optimized for its specific function, enabling the display device to achieve low power consumption in peripheral areas while maintaining high performance in display areas.
2Use of energy by stationary object
If different types of transistors are used on the same substrate, then power consumption is reduced, but the manufacturing process becomes complex with multiple mask processes
Solution Approach 1:
The patent merges the manufacturing processes of low-power and high-speed transistors by using a common gate electrode formation process. Both transistor types share the same gate electrode layer and gate insulating layer formation steps, significantly reducing the number of mask processes required. This integration maintains the benefits of different transistor types while simplifying the overall manufacturing complexity.
Solution Approach 2:
The patent creates a universal gate electrode structure that serves both low-power and high-speed transistors. The gate electrode and gate insulating layer are formed once and serve dual purposes for both transistor types, eliminating the need for separate gate formation processes and reducing manufacturing steps while maintaining distinct transistor characteristics through different channel layer materials.
3Duration of action of moving object
If low-speed driving is used to extend battery life, then power consumption decreases, but flicker issues occur and video quality deteriorates
Solution Approach 1:
The patent changes the electrical parameters of the driving circuit transistors by using low-power transistor designs with optimized threshold voltages and channel structures. These parameter changes enable the driving circuits to operate efficiently at lower speeds without causing flicker, allowing the display to maintain video quality while extending battery life through reduced power consumption during peripheral operations.
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 configuration enables optimized performance for portable and wearable displays by reducing power consumption, preventing flicker issues during low-speed driving, and maintaining video quality, thus extending battery life and improving display performance.
Implementation Method 1
a hydrogenation process to stabilize the polycrystalline layer
Implementation Method 2
thermal treatment to stabilize the oxide layer
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Provided are a thin film transistor (TFT) substrate and a display using the same. A display includes: a first TFT, including: a polycrystalline semiconductor layer, a first gate electrode thereover, a first source electrode, and a first drain electrode, a second TFT, including: a second gate electrode, an oxide semiconductor layer over the second gate electrode, a second source electrode, and a second drain electrode, an intermediate insulating layer including a nitride layer, on the first gate electrode, and an oxide layer covering the second gate electrode, on the intermediate insulating layer, on the oxide layer, and overlapping the second gate electrode, wherein the first source, first drain, and second gate electrodes are between the intermediate insulating layer and the oxide layer, and wherein the second source and the second drain electrodes are on the oxide semiconductor layer.