Characterization of Acoustic Losses in Interdigitated VHF to mmWave Piezoelectric M/NEMS Resonators

TL;DR

This paper introduces a comprehensive methodology combining modeling, FEA, and experiments to characterize acoustic losses in interdigitated piezoelectric M/NEMS resonators across various frequencies and materials.

Contribution

It presents a frequency-independent, technology-agnostic approach to model and validate acoustic losses in piezoelectric resonators using experimental data.

Findings

Model accurately predicts mechanical quality factor (Qm) and losses.

Validated across multiple resonator technologies and materials.

Provides insights into loss mechanisms at different frequency bands.

Abstract

This work reports on a technology-agnostic and frequency-independent methodology combining a-priori modeling, Finite Element Analysis (FEA), and experimental results for the characterization of acoustic losses in interdigitated piezoelectric micro- and nano-electromechanical (M/NEMS) resonators. The proposed approach models the mechanical quality factor (Qm) and its dependency on piezoelectric (Qpiezo) and metal (Qmetal) acoustic losses, as a function of the mode of vibration dispersion characteristics. The model is finally experimentally validated by exploiting the intrinsic on-chip multifrequency manufacturability of interdigitated devices. A broad range of available resonator technologies, frequencies, and piezoelectric materials are investigated for this purpose, including bulk X-cut Lithium Niobate (XLN) leaky surface acoustic wave resonators operating at Ultra High Frequency (UHF), thin film XLN Lamb Wave resonators spanning between Very High Frequency (VHF) and the Ku band, and Aluminum Nitride (AlN) and scandium-doped AlN (ScAlN) cross-sectional lame' mode resonators ranging from the Ku to Ka band (mmWave).