Oxide Semiconductor Purification via Oxygen Ion Implantation
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Solution Overview
Problem
Semiconductor devices using oxide semiconductors face issues with variation in threshold voltage and increased off-state current due to impurities like hydrogen and oxygen deficiency, which affect reliability and power consumption.
Innovation Solution
A method involving the addition of high-energy oxygen to the oxide semiconductor layer using ion implantation or ion doping, followed by heat treatment to remove impurities and maintain oxygen levels, resulting in a highly purified semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If heat treatment is performed to remove impurities from the oxide semiconductor layer, then impurity concentration is reduced, but oxygen deficiency is generated
Solution Approach 1:
Oxygen is added to the oxide semiconductor layer before heat treatment through ion implantation or ion doping. This preliminary oxygen addition ensures that when heat treatment is subsequently applied to remove impurities, the oxygen already present in the layer prevents oxygen deficiency from occurring, thus resolving the contradiction between impurity removal and oxygen maintenance
Solution Approach 2:
High-energy oxygen ions are introduced as an intermediary substance that facilitates the removal of impurities while maintaining oxygen balance. The oxygen ions penetrate the oxide semiconductor layer and form oxygen-rich regions that act as a buffer during heat treatment, preventing oxygen deficiency while allowing impurity elimination
2Manufacturing precision
If conventional heat treatment is used to remove impurities, then hydrogen and water are reduced, but strongly bonded impurities remain
Solution Approach 1:
The energy state of oxygen is changed by introducing it as high-energy oxygen ions through ion implantation or ion doping. This parameter change enables the oxygen to break strong bonds between hydrogen/oxygen and metal atoms in the oxide semiconductor, allowing removal of impurities that conventional low-energy heat treatment cannot eliminate
Solution Approach 2:
High-energy oxygen ions are introduced before final heat treatment to break strong bonds between impurities and metal atoms. This preliminary high-energy action enables subsequent heat treatment to effectively remove even strongly bonded impurities like hydrogen and hydroxyl groups that were previously difficult to eliminate
3Area of stationary object
If oxide semiconductor is used for transistor, then large substrate area can be covered, but threshold voltage variation and off-state current increase due to impurities
Solution Approach 1:
Hydrogen and water impurities are extracted from the oxide semiconductor layer through heat treatment after oxygen addition. This extraction process removes the harmful impurities that cause threshold voltage variation and increased off-state current, allowing the oxide semiconductor to be used for large-area substrates without sacrificing device reliability
Solution Approach 2:
The concentration of impurities in the oxide semiconductor layer is changed through the combined process of oxygen ion implantation and heat treatment. This parameter change reduces hydrogen and water content to levels that prevent threshold voltage variation and maintain low off-state current, enabling reliable large-area device fabrication
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 reduces impurities in the oxide semiconductor layer, stabilizing the threshold voltage and minimizing off-state current, leading to a highly reliable and low-power semiconductor device with improved productivity.
Implementation Method 1
addition of high-energy oxygen to the oxide semiconductor layer using ion implantation or ion doping
Implementation Method 2
addition of high-energy oxygen to the oxide semiconductor layer using ion implantation or ion doping
Implementation Method 3
heat treatment to remove impurities and maintain oxygen levels
Implementation Method 4
heat treatment for removing impurities may be performed on the oxide semiconductor layer
Data Source
AI summary
It is an object to provide a highly reliable semiconductor device, a semiconductor device with low power consumption, a semiconductor device with high productivity, and a method for manufacturing such a semiconductor device. Impurities left remaining in an oxide semiconductor layer are removed without generating oxygen deficiency, and the oxide semiconductor layer is purified to have an extremely high purity. Specifically, after oxygen is added to the oxide semiconductor layer, heat treatment is performed on the oxide semiconductor layer to remove the impurities. In order to add oxygen, it is preferable to use a method in which oxygen having high energy is added by an ion implantation method, an ion doping method, or the like.