Hybrid TFT Substrate with Overlapping Oxide and Poly-Si Transistors
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Solution Overview
Problem
Conventional display technologies face limitations in reducing power consumption, especially in portable and wearable devices, due to the limitations of existing thin film transistor substrates.
Innovation Solution
A thin film transistor substrate is designed with both a polycrystalline semiconductor and an oxide semiconductor TFT on the same substrate, where the oxide semiconductor TFT overlaps the polycrystalline TFT, optimizing power consumption and manufacturing efficiency by reducing the number of mask processes and leveraging the low off-current characteristics of oxide semiconductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional thin film transistor substrates are used, then manufacturing processes are simpler, but power consumption cannot be reduced sufficiently
Solution Approach 1:
The patent merges two different transistor types (oxide semiconductor TFT and polycrystalline semiconductor TFT) into a single substrate, creating a hybrid structure that combines the low off-current characteristics of oxide semiconductors with the high mobility of polycrystalline semiconductors, thereby reducing overall power consumption while maintaining performance
Solution Approach 2:
The patent transitions from using a single transistor type to employing two different transistor types on the same substrate, adding dimensional diversity to the device architecture. This allows optimization of different functional regions with appropriate transistor types
2Loss of energy
If oxide semiconductor TFTs are used, then standby power consumption is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies different semiconductor materials to different regions where they are most effective: oxide semiconductor TFTs are used in regions requiring low off-current (such as switching elements), while polycrystalline semiconductor TFTs are used in regions requiring high mobility (such as driving elements), optimizing both power consumption and manufacturability
3Reliability
If multiple mask processes are used, then transistor characteristics can be optimized, but manufacturing efficiency decreases
Solution Approach 1:
The patent designs a unified manufacturing process that can produce both oxide semiconductor TFTs and polycrystalline semiconductor TFTs using the same mask processes and fabrication steps, making the manufacturing system multi-functional and eliminating the need for separate process lines
Data Source
AI summary
A thin film transistor (TFT) substrate and a display device using the same are disclosed. The TFT substrate includes a base substrate, a first TFT having a polycrystalline semiconductor and disposed on the base substrate, and a second TFT having an oxide semiconductor and disposed on the first TFT. The second TFT overlaps at least a portion of the first TFT in a plan view.