Geometric Tuning of Stress in Predisplaced Silicon Nitride Resonators

Area of Science:

• Solid-state physics
• Materials science
• Nanotechnology

Background:

• Prestressed resonators are crucial for various applications.
• Understanding stress-dependent dissipation mechanisms is essential.
• Existing methods for tuning resonator tension are limited.

Purpose of the Study:

• To introduce a novel method for geometrically tuning tension in silicon nitride (Si3N4) resonators.
• To enable precise control over resonator properties like frequency and damping.
• To facilitate the study of stress-dependent dissipation mechanisms.

Main Methods:

• Fabrication of Si3N4 strings with designed predisplacement.
• Release of resonators from the substrate.
• Characterization of static displacement using scanning electron microscopy (SEM).
• Finite-element simulations for stress determination.
• Sensing of in- and out-of-plane eigenmodes with on-chip Mach-Zehnder interferometers.
• Extraction of resonance frequencies and quality factors.

Main Results:

• Geometrically controlled stress was achieved in Si3N4 resonators.
• SEM results matched finite-element simulations, enabling quantitative stress determination.
• Resonance frequencies and quality factors were successfully extracted.
• Geometrically controlled stress tuned both frequencies and damping rates.
• A model quantitatively capturing stress-dependent dissipation was developed.

Conclusions:

• The novel method allows precise geometric tuning of tension in Si3N4 resonators.
• This technique provides control over frequency, damping rate, and frequency ratios.
• The predisplacement shape offers additional flexibility for targeted resonator performance.