IGZO Thin Film Transistor Oxygen Content Control
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Solution Overview
Problem
IGZO semiconductors used as channel layers in thin film transistors face instability due to oxygen desorption during high-temperature processing, leading to changes in oxygen content and compromised transistor characteristics.
Innovation Solution
Controlling the oxygen content of IGZO semiconductors within the range of 87% to 95% stoichiometric conditions, using techniques like auger electron spectroscopy and X-ray photoelectron spectroscopy for precise analysis, and incorporating baking treatments to maintain stable oxygen levels during the production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IGZO semiconductor is used as channel layer for TFT, then high electron mobility and low leakage current are achieved, but stable transistor characteristics cannot be maintained due to oxygen desorption during high-temperature processing
Solution Approach 1:
The patent applies preliminary action by forming a protective layer over the IGZO semiconductor layer before subsequent high-temperature processing steps. This protective layer is prepared in advance to prevent oxygen desorption during later baking or heating processes, thereby maintaining the oxygen content and stabilizing the transistor characteristics without requiring post-processing adjustments
Solution Approach 2:
The patent employs an inert atmosphere approach by conducting baking or heating processes in a nitrogen or rare gas environment. This inert atmosphere prevents oxygen loss from the IGZO semiconductor layer during high-temperature processing, maintaining the stoichiometric composition and ensuring stable transistor characteristics while enabling necessary thermal processing steps
2Ease of manufacture
If high temperature processing (200°C or higher) is applied for forming protective layers and interlayer insulating films, then proper film formation is achieved, but oxygen desorption occurs in IGZO semiconductor leading to composition changes
Solution Approach 1:
The patent applies inert atmosphere by performing baking or heating processes in a nitrogen or rare gas environment. This prevents oxygen desorption from the IGZO semiconductor layer during high-temperature processing, allowing proper formation of protective layers and interlayer insulating films while maintaining precise control over the oxygen content and stoichiometric composition of the semiconductor layer
Solution Approach 2:
The patent uses preliminary action by forming a protective layer over the IGZO semiconductor layer before subsequent high-temperature processing. This pre-formed protective layer acts as a barrier that prevents oxygen loss during baking or heating, enabling ease of manufacture for protective layer formation while maintaining manufacturing precision for oxygen content control
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 approach ensures stable and credible transistor characteristics for thin film transistors, enhancing their performance and reliability, particularly in display devices.
Implementation Method 1
an oxide semiconductor can be suitably used as a channel layer of a thin film transistor... formed by including the oxide semiconductor... can be produced by simple procedures... formed into a film by a sputtering system
Implementation Method 2
The oxygen content and composition of the oxide semiconductor layer were analyzed by auger electron spectroscopy (AES)... the oxygen content of the oxide semiconductor layer was 9.0 at %
Implementation Method 3
X-ray photoelectron spectroscopy (XPS)... preferable compositions of constituent atoms of oxide semiconductors... can be analyzed by X-ray photoelectron spectroscopy (XPS)
Data Source
AI summary
The present invention provides an oxide semiconductor capable of achieving a thin film transistor having stable transistor characteristics, a thin film transistor having a channel layer formed of the oxide semiconductor and a production method thereof, and a display device equipped with the thin film transistor. The oxide semiconductor of the present invention is an oxide semiconductor for a thin film transistor. The oxide semiconductor includes indium, gallium, zinc, and oxygen as constituent atoms, and the oxygen content of the oxide semiconductor is 87% to 95% of the stoichiometric condition set as 100%, in terms of atomic units.