Oxide Semiconductor Stability via Dehydration and Oxygen Doping
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Solution Overview
Problem
The electrical conductivity of oxide semiconductors can vary due to the presence of hydrogen or moisture, leading to unstable electrical characteristics in transistors, which affects the reliability and performance of semiconductor devices.
Innovation Solution
A manufacturing method for semiconductor devices that involves dehydration or dehydrogenation treatment and oxygen doping to remove hydrogen atoms and supply oxygen atoms to the oxide semiconductor film, ensuring a stoichiometric excess of oxygen to stabilize the electrical characteristics and reduce threshold voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If hydrogen or moisture is present in the oxide semiconductor during manufacturing, then the oxide semiconductor can be easily formed, but the electrical conductivity becomes unstable and electrical characteristics vary
Solution Approach 1:
The patent applies preliminary action by performing dehydration and dehydrogenation heat treatment on the oxide semiconductor film before subsequent processing steps. This pre-treatment removes hydrogen and moisture that would otherwise cause electrical characteristic variations, ensuring stable threshold voltage and conductivity from the outset.
Solution Approach 2:
The patent changes physical parameters by controlling heat treatment temperature (400-700°C) and atmosphere (oxygen or inert gas) to remove hydrogen and moisture. It also controls oxygen partial pressure during film formation to optimize the balance between ease of formation and electrical stability.
2Reliability
If dehydration and dehydrogenation heat treatment is performed, then electrical characteristics are stabilized, but manufacturing process complexity increases
Solution Approach 1:
The patent merges multiple functions into a single heat treatment step that simultaneously performs dehydration and dehydrogenation. This combined treatment is conducted in one processing cycle using oxygen or inert gas atmosphere, reducing the number of separate steps while achieving stable electrical characteristics.
Solution Approach 2:
The heat treatment process serves multiple functions: it removes hydrogen, removes moisture, stabilizes the oxide semiconductor structure, and prepares the film for subsequent processing. This multi-functional approach reduces overall process complexity while achieving reliability goals.
3Reliability
If oxygen doping treatment is performed to supply excess oxygen, then electrical characteristics are stabilized, but manufacturing time increases
Solution Approach 1:
The patent performs oxygen supply during the initial film formation process or in conjunction with the dehydration heat treatment, before subsequent processing steps. This preliminary oxygen incorporation ensures stable electrical characteristics are established early, reducing the need for additional oxygen doping steps later.
Solution Approach 2:
The patent controls oxygen partial pressure and temperature parameters during film formation and heat treatment to achieve optimal oxygen incorporation. By optimizing these parameters, the process achieves stable electrical characteristics without requiring excessive additional processing time.
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 results in highly reliable semiconductor devices with stable electrical characteristics, reducing variations in threshold voltage and enhancing the devices' resistance to bias-temperature stress and light exposure.
Implementation Method 1
heat treatment is performed on the oxide semiconductor film so that a hydrogen atom in the oxide semiconductor film is removed
Implementation Method 2
oxygen doping treatment is performed on the oxide semiconductor film, so that an oxygen atom is supplied into the oxide semiconductor film
Data Source
AI summary
One object of one embodiment of the present invention is to provide a highly reliable semiconductor device including an oxide semiconductor, which has stable electrical characteristics. In a method for manufacturing a semiconductor device, a first insulating film is formed; source and drain electrodes and an oxide semiconductor film electrically connected to the source and drain electrodes are formed over the first insulating film; heat treatment is performed on the oxide semiconductor film so that a hydrogen atom in the oxide semiconductor film is removed; oxygen doping treatment is performed on the oxide semiconductor film, so that an oxygen atom is supplied into the oxide semiconductor film; a second insulating film is formed over the oxide semiconductor film; and a gate electrode is formed over the second insulating film so as to overlap with the oxide semiconductor film.