Electrothermal Actuators for SiO₂ Photonic MEMS.

Area of Science:

• Microelectromechanical systems (MEMS)
• Photonics
• Materials Science

Background:

• Thick silicon dioxide structures can fracture due to residual stress.
• Integrating actuators with photonic waveguides is challenging.
• Precise chip-to-chip alignment is crucial for automated systems.

Purpose of the Study:

• To design, fabricate, and characterize electrothermal bimorph actuators.
• To enable mechanically-flexible, positionable photonic waveguide structures.
• To explore their application in sub-micrometer precision chip-to-chip alignment.

Main Methods:

• Fabrication of polysilicon on thick silicon dioxide beams.
• Application of a reinforcement method to prevent fracturing.
• Characterization of post-release deformation and actuation response (quasi-static and dynamic).

Main Results:

• Post-release curvature observed in 800 μm beams, with free ends ~80 μm above the chip.
• Out-of-plane deflection of ~11 μm at 60 mW (actuator temperature ~240 °C).
• Actuation force of ~750 μN at 120 mW for 800 μm actuators.

Conclusions:

• The developed material platform enables integrated, flexible photonic waveguide structures.
• The electrothermal bimorph actuators demonstrate significant deflection and force for precise alignment.
• This technology offers a novel approach for highly automated, sub-micrometer precision chip-to-chip alignment.