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Fabrication Process Research for Silicon-Waveguide-Integrated Cavity Optomechanical Devices Using Magnesium Fluoride
Chengwei Xian1,2, Pengju Kuang1, Ning Fu1
1School of Information and Communication Engineering, Sichuan Provincial Engineering Research Center of Communication Technology for Intelligent IoT, University of Electronic Science and Technology of China, Chengdu 611731, China.
A new magnesium fluoride (MgF2) protective layer prevents silicon oxide (SiO2) etching during fabrication of optomechanical devices. This method successfully protects long silicon waveguides, improving production yields for high-precision sensing applications.
Area of Science:
- Photonics and Microelectromechanical Systems (MEMS)
- Materials Science for Integrated Devices
Background:
- Integrated silicon-waveguide-based cavity optomechanical devices are crucial for high-precision sensing.
- Fabrication challenges arise from the susceptibility of the silicon oxide (SiO2) layer to etching during hydrofluoric acid (HF) release of microstructures.
- This etching leads to waveguide collapse and reduced production yields.
Purpose of the Study:
- To address the critical challenge of long-range waveguide collapse during hydrofluoric acid (HF) etching in optomechanical device fabrication.
- To propose and validate a novel selective protection process for silicon oxide (SiO2) layers.
Main Methods:
- A selective protection process utilizing a magnesium fluoride (MgF2) thin film was developed.
- MgF2 protective layers were deposited over waveguide regions using optical coating technology.
- Localized protection of specific SiO2 areas during HF etching was achieved.
Main Results:
- The MgF2 protective layer successfully prevented SiO2 etching during HF release.
- Silicon waveguides with lengths up to 5000 μm were successfully released.
- A significant improvement in production yield for optomechanical devices was demonstrated.
Conclusions:
- The MgF2 selective protection process is a compatible and efficient strategy for fabricating robust photonic-microelectromechanical integrated devices.
- This method overcomes critical fabrication challenges, enabling the production of high-performance optomechanical sensors.
- The study provides a viable solution for improving yields in integrated photonics manufacturing.
