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Published on: April 11, 2017
Summary
Hydrogen exposure during amorphous silicon film growth allows control over film structure, enabling a transition from amorphous to crystalline states and substrate-selective growth. This method utilizes hydrogen
Area of Science:
- Materials Science
- Surface Science
- Thin Film Deposition
Background:
- Amorphous silicon (a-Si) films are crucial in various electronic applications.
- Controlling the structure of a-Si during growth is challenging.
- Strained bonds formed during deposition can lead to defects and non-equilibrium structures.
Purpose of the Study:
- To investigate the role of hydrogen in modifying the structure of amorphous silicon films.
- To achieve continuous variation in film composition from amorphous to crystalline.
- To enable substrate-selective growth by controlling hydrogen exposure.
Main Methods:
- Periodic interruption of amorphous silicon film growth.
- Exposure of the grown material to hydrogen at controlled intervals.
- In-situ observation of film structure evolution using scanning tunneling microscopy (STM).
- Development of a model for hydrogen's role in film restructuring.
Main Results:
- Hydrogen atoms selectively eliminate strained Si-Si bonds.
- Continuous tuning of film structure from non-equilibrium amorphous to crystalline is achieved.
- Substrate-selective growth is demonstrated by discriminating between Si-Si bonds on different substrates.
- STM observations directly visualize structural changes during hydrogen exposure.
Conclusions:
- Periodic hydrogen exposure is an effective method for controlling amorphous silicon film structure.
- This technique allows for the continuous modification of film properties and substrate-selective deposition.
- The presented model elucidates the mechanism of hydrogen-mediated structural evolution in silicon films.
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