Gate Insulating Film Structure for Reliable Display Transistors
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Solution Overview
Problem
Transistors in display devices degrade over time, leading to reduced device reliability and image quality, with existing techniques failing to effectively address bidirectional degradation and instantaneous afterimages.
Innovation Solution
A display device with a transistor structure featuring a gate insulating film having different component concentrations in its first and second portions, where the first portion is closer to the active layer and the second portion is closer to the gate electrode, effectively removing traps at the interface between the active layer and the gate insulating film, thereby improving both positive and negative degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transistor structures are used, then manufacturing is simpler, but transistor degradation occurs leading to reduced reliability and image quality
Solution Approach 1:
The gate insulating film is divided into multiple layers including a first gate insulating film and a second gate insulating film with different material compositions and functions. This segmentation allows each layer to address specific degradation mechanisms independently, improving overall transistor reliability while managing the complexity through functional specialization.
Solution Approach 2:
Different regions of the gate insulating film structure are assigned different material properties: the first gate insulating film uses a material with high dielectric constant for effective charge control, while the second gate insulating film uses a material resistant to trap formation. This local quality differentiation optimizes performance for specific functions within the overall structure.
2Reliability
If existing techniques are applied, then some degradation is addressed, but instantaneous afterimage issues persist
Solution Approach 1:
A protective film is introduced as an intermediary layer between the gate insulating film and the active layer. This protective film acts as a mediator that prevents direct interaction causing trap formation at the interface, thereby eliminating the root cause of instantaneous afterimages while maintaining the necessary electrical functions.
Solution Approach 2:
The gate insulating film structure employs composite materials with different properties in different layers. The combination of high-k dielectric material and trap-resistant material creates a composite structure that simultaneously achieves effective charge control and prevents trap formation, resolving the instantaneous afterimage issue.
3Reliability
If uniform gate insulating film is used, then manufacturing is easier, but traps form at the interface causing degradation
Solution Approach 1:
The gate insulating film formation process is segmented into multiple deposition steps, each creating a specific layer with tailored properties. This segmentation enables precise control over the material composition and thickness of each layer, preventing trap formation at interfaces while maintaining manufacturing feasibility through standardized multi-step processes.
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
The solution prevents instantaneous afterimages and enhances transistor reliability by improving bidirectional degradation, maintaining image quality and device performance.
Implementation Method 1
a gate insulating film having a structure capable of removing a trap generated at an interface between an active layer and the gate insulating film
Implementation Method 2
forming a gate insulating film including a first portion and a second portion by depositing an insulating material on the active layer with a deposition gas
Data Source
AI summary
Disclosed are a display device and a manufacturing method thereof. More particularly, a display device including a substrate, a buffer layer disposed on the substrate, an active layer disposed on the buffer layer, a gate insulating film disposed on the active layer, and a gate electrode disposed on the gate insulating film, wherein the gate insulating film includes a first portion and a second portion, wherein the first portion is closer to the active layer than the second portion and the second portion is closer to the gate electrode than the first portion, and the gate insulating film includes two or more elements having different component concentrations in the first portion and the second portion, and a manufacturing method thereof are provided to provide a transistor structure having high reliability.