Mechanical dissipation by substrate-mode coupling in SiN resonators

TL;DR

This paper investigates how substrate-mode coupling affects mechanical dissipation in SiN nanomechanical resonators, revealing that resonance frequency alignment with substrates increases dissipation, and offers design guidelines for high-precision applications.

Contribution

It provides an analytical model and experimental validation of substrate-mode coupling as a dissipation mechanism in nanomechanical resonators, highlighting its dependence on positioning and mounting.

Findings

Resonance frequency matching increases dissipation.

Coupling can occur between adjacent resonators.

Positioning and mounting influence dissipation levels.

Abstract

State-of-the-art nanomechanical resonators are heralded as a central component for next-generation clocks, filters, resonant sensors and quantum technologies. To practically build these technologies will require monolithic integration of microchips, resonators and readout systems. While it is widely seen that mounting microchip substrates into a system can greatly impact the performance of high-Q resonators, a systematic study has remained elusive, owing to the variety of physical processes and factors that influence the dissipation. Here, we analytically analyze a mechanism by which substrates couple to resonators manufactured on them, and experimentally demonstrate that this coupling can increase the mechanical dissipation of nanomechanical resonators when the resonance frequencies of resonator and substrate coincide. More generally, we then show a similar coupling mechanism can exist between two adjacent resonators. Since the substrate-mode coupling mechanism strongly depends on both the resonator position on the substrate and the mounting of the substrate, this work provides key design guidelines for high-precision nanomechanical technologies.