Hybrid TFT Substrate with Intermediate Insulating Layer for Low Power
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Solution Overview
Problem
Existing flat panel display technologies face challenges in achieving low power consumption and efficient manufacturing processes for thin film transistor substrates with multiple types of transistors, particularly for portable and wearable devices.
Innovation Solution
A thin film transistor substrate is designed with two types of transistors, one using polycrystalline semiconductor material for driver ICs and the other using oxide semiconductor material for switching elements, optimized through a top-gate and bottom-gate structure, respectively, with an intermediate insulating layer and etch-stopper layer to manage hydrogen diffusion and thermal treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single type of thin film transistor is used on the substrate, then the manufacturing process is simple, but the power consumption cannot be optimized for portable devices
Solution Approach 1:
The substrate is divided into two distinct regions: a first region containing polycrystalline thin film transistors and a second region containing oxide semiconductor thin film transistors. This segmentation allows each transistor type to be optimized for specific functions (driver circuits vs. switching elements), achieving low power consumption without requiring complete redesign of the entire transistor system
Solution Approach 2:
Different transistor types are selectively applied to different functional areas: polycrystalline TFTs are used in the first region for high-current driver circuits, while oxide semiconductor TFTs are used in the second region for low-leakage switching elements. This local quality differentiation optimizes power consumption for portable devices while maintaining manufacturing efficiency
2Use of energy by moving object
If two different types of thin film transistors are manufactured on the same substrate, then power consumption is reduced, but the number of mask processes increases
Solution Approach 1:
A unified mask pattern design is employed that serves multiple functions: it defines both the first transistor region and the second transistor region, controls the formation of different semiconductor layers, and manages the intermediate insulating layer structure. This multi-functional mask approach enables manufacturing of dual transistor types without increasing the number of mask processes
Solution Approach 2:
An intermediate insulating layer with specific etch selectivity is formed in advance between the two transistor regions. This preliminary action establishes clear boundaries and facilitates subsequent processing steps, allowing efficient manufacturing of different transistor types on the same substrate without requiring additional mask processes
3Power
If polycrystalline semiconductor material is used for driver ICs, then the driving capability is sufficient, but the leakage current is high
Solution Approach 1:
Polycrystalline semiconductor material is selectively applied in the first region where high driving capability is needed for driver ICs, while oxide semiconductor material is used in the second region where low leakage current is critical for switching elements. This local material differentiation simultaneously achieves sufficient driving power and minimal energy loss
4Loss of energy
If oxide semiconductor material is used for switching elements, then the leakage current is low, but the driving capability is insufficient
Solution Approach 1:
Oxide semiconductor material is selectively deployed in the second region for switching elements where low leakage current is the primary requirement, while polycrystalline material handles the driving function in the first region. This spatial differentiation of material properties achieves both low energy loss and sufficient driving capability
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 reduced power consumption, improved video quality, and extended battery life in portable and wearable displays by optimizing transistor characteristics and manufacturing efficiency.
Implementation Method 1
an intermediate insulating layer including a nitride layer and an oxide layer on the nitride layer, the intermediate insulating layer being disposed on the first gate electrode and the second gate electrode and under the oxide semiconductor layer
Data Source
AI summary
Provided are a thin film transistor substrate and a display using the same. A thin film transistor substrate includes: a substrate, a first thin film transistor disposed on the substrate, the first thin film transistor including: a polycrystalline semiconductor layer, a first gate electrode on the polycrystalline semiconductor layer, a first source electrode, and a first drain electrode, a second thin film transistor disposed on the substrate, the second thin film transistor including: a second gate electrode, an oxide semiconductor layer on the second gate electrode, a second source electrode, and a second drain electrode, an intermediate insulating layer including a nitride layer and an oxide layer on the nitride layer, the intermediate insulating layer being disposed on the first gate electrode and the second gate electrode and under the oxide semiconductor layer, and an etch-stopper layer disposed on the oxide semiconductor layer.