Oxide TFT Display Electrodes With Dehydration for Aperture and Reliability
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Solution Overview
Problem
Conventional display panels using oxide semiconductors face challenges in improving aperture ratio and reliability due to the use of conductive films with light-transmitting properties, and the manufacturing process does not adequately address impurities such as moisture in the semiconductor layers.
Innovation Solution
A manufacturing method for semiconductor devices that involves forming a gate electrode layer, gate insulating layer, and oxide semiconductor layer, followed by dehydration or dehydrogenation heat treatment in an oxygen or inert gas atmosphere to reduce impurities, and slow cooling to enhance the purity and performance of the oxide semiconductor film, thereby improving the reliability and aperture ratio of the thin film transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conductive film with light-transmitting property is used for the electrode material, then the transparency of the electrode is improved, but the aperture ratio cannot be improved and reliability is compromised
Solution Approach 1:
The patent uses a composite structure consisting of a transparent conductive film (ITO or similar) combined with a metal film (Al, Mo, or Ti) to form the electrode. This composite structure maintains the light-transmitting property of the transparent conductive film while adding the reliability and mechanical strength of the metal film, resolving the contradiction between transparency and reliability
Solution Approach 2:
The transparent conductive film serves multiple functions: it provides electrical conductivity, maintains transparency for light transmission, and acts as an adhesive layer between the metal film and the semiconductor layer. This multi-functionality allows the electrode to achieve both transparency and reliability simultaneously
2Ease of manufacture
If conventional manufacturing process is used without dehydration treatment, then the manufacturing process is simpler, but impurities such as moisture remain in the oxide semiconductor film reducing reliability
Solution Approach 1:
The patent performs dehydration and dehydrogenation treatment of the oxide semiconductor film before forming the source and drain electrodes. This preliminary action removes moisture and hydrogen impurities that would otherwise remain in the film, ensuring high reliability of the oxide semiconductor while maintaining a relatively simple manufacturing process
Solution Approach 2:
The patent applies heat treatment at specific temperature ranges (typically 200-450°C) in a controlled atmosphere to dehydrate and dehydrogenate the oxide semiconductor film. By controlling the temperature and atmosphere parameters, the process effectively removes impurities while preventing damage to other layers, achieving high reliability without excessive process complexity
3Reliability
If metal auxiliary wiring is provided to reduce electric resistance of additional capacitor electrode, then the electric resistance is reduced, but the aperture ratio is compromised due to additional metal layers
Solution Approach 1:
The patent combines the auxiliary wiring function with the existing transparent conductive film and metal film structure of the additional capacitor electrode. By merging these functions into a single integrated electrode structure, the patent reduces electric resistance through the metal film while maintaining the transparency and aperture ratio provided by the transparent conductive film, avoiding the need for separate metal auxiliary wiring layers
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 method effectively reduces moisture and impurities in the oxide semiconductor layer, leading to improved electric characteristics and high reliability of the thin film transistor, while also enhancing the aperture ratio by using light-transmitting materials for the electrodes and semiconductor layers.
Implementation Method 1
a heat treatment for reducing moisture and the like which are impurities and for improving the purity of the oxide semiconductor film (a heat treatment for dehydration or dehydrogenation) is performed
Implementation Method 2
a heat treatment for reducing moisture and the like which are impurities and for improving the purity of the oxide semiconductor film (a heat treatment for dehydration or dehydrogenation) is performed
Implementation Method 3
a heat treatment for reducing moisture and the like which are impurities and for improving the purity of the oxide semiconductor film is performed
Data Source
AI summary
It is an object to manufacture and provide a highly reliable display device including a thin film transistor with a high aperture ratio which has stable electric characteristics. In a manufacturing method of a semiconductor device having a thin film transistor in which a semiconductor layer including a channel formation region is formed using an oxide semiconductor film, a heat treatment for reducing moisture and the like which are impurities and for improving the purity of the oxide semiconductor film (a heat treatment for dehydration or dehydrogenation) is performed. Further, an aperture ratio is improved by forming a gate electrode layer, a source electrode layer, and a drain electrode layer using conductive films having light transmitting properties.