Oxide Semiconductor Purification via Insulating-Layer Oxygen Diffusion
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Solution Overview
Problem
Oxide semiconductor transistors exhibit variations in electric characteristics due to impurities like hydrogen, moisture, and oxygen composition deviations during thin film formation, leading to unstable performance.
Innovation Solution
A method involving the formation of an intrinsic oxide semiconductor layer by removing impurities such as hydrogen and moisture through an oxide insulating layer, followed by oxygen introduction and heat treatment to achieve stable electric characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen is introduced through an oxide insulating layer and heat treatment is performed to remove impurities, then the oxide semiconductor layer becomes highly purified with stable electric characteristics, but the manufacturing process complexity increases
Solution Approach 1:
The oxide insulating layer is formed beforehand to serve as an oxygen source during subsequent heat treatment. This preliminary preparation allows the oxide semiconductor layer to be highly purified through oxygen diffusion and impurity removal in one integrated process, rather than requiring multiple separate purification steps.
Solution Approach 2:
The oxide insulating layer acts as an intermediary medium that facilitates oxygen transfer to the oxide semiconductor layer. It serves as both a protective layer and an oxygen reservoir, enabling controlled oxygen introduction without direct exposure to external oxygen sources during heat treatment.
2Reliability
If multiple processing steps are performed to achieve highly purified oxide semiconductor layer, then the electric characteristics become more stable, but the manufacturing time increases
Solution Approach 1:
The formation of the oxide insulating layer and the heat treatment process are merged into an integrated sequence where the insulating layer is formed immediately before heat treatment. This combination allows the oxide insulating layer to function as both a structural component and an oxygen source during purification, eliminating the need for separate oxygen introduction steps.
Solution Approach 2:
The oxide insulating layer performs multiple functions simultaneously: it serves as a protective barrier, an oxygen reservoir for diffusion during heat treatment, and a means to control the purification process. This multi-functionality reduces the total number of processing steps required to achieve highly purified oxide semiconductor.
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 approach results in a highly purified, intrinsic oxide semiconductor layer with stable electric characteristics and reduced temperature dependence, enhancing the reliability of semiconductor devices.
Implementation Method 1
introducing oxygen to the oxide semiconductor layer through the oxide insulating layer
Implementation Method 2
heat treatment is performed; Through these steps of oxygen introduction and heat treatment, impurities such as hydrogen, moisture, a hydroxyl group, or hydride are intentionally removed from the oxide semiconductor layer
Implementation Method 3
a bond between a metal included in the oxide semiconductor and hydrogen or a bond between the metal and a hydroxyl group is cut, and the hydrogen or the hydroxyl group is reacted with oxygen to produce water
Data Source
AI summary
In a transistor including an oxide semiconductor layer, an oxide insulating layer is formed so as to be in contact with the oxide semiconductor layer. Then, oxygen is introduced (added) to the oxide semiconductor layer through the oxide insulating layer, and heat treatment is performed. Through these steps of oxygen introduction and heat treatment, impurities such as hydrogen, moisture, a hydroxyl group, or hydride are intentionally removed from the oxide semiconductor layer, so that the oxide semiconductor layer is highly purified.