Impedance-matched High-overtone Bulk Acoustic Resonator
Megumi Kurosu, Daiki Hatanaka, Ryuichi Ohta, Hiroshi Yamaguchi,, Yoshitaka Taniyasu, and Hajime Okamoto

TL;DR
This paper reports the fabrication of a nearly impedance-matched high-quality high-overtone bulk acoustic resonator (HBAR) using epitaxial AlN on SiC, achieving high frequency, high Q-factor, and broadband phonon modes for advanced RF applications.
Contribution
The study introduces a novel impedance-matched HBAR with epitaxial AlN directly grown on SiC, eliminating metal layers and enhancing performance for RF and high-frequency acoustic systems.
Findings
Achieved impedance matching verified by FSR variation.
Reproduced FSR spectra with Mason model.
Realized broadband phonon modes up to 26.5 GHz.
Abstract
A high-overtone bulk acoustic resonator (HBAR), in which a piezoelectric transducer is set on an acoustic cavity, has been attracting attention in both fundamental research and RF applications due to its scalability, high frequency, and high quality factor. The acoustic impedance matching in HBARs is crucial for efficient acoustic power transfer from the piezoelectric transducer to the cavity. However, impedance mismatch remains in most HBARs due to the metal layer insertion between the piezoelectric layer and cavity substrate. In this study, we fabricated a nearly impedance-matched high-quality HBAR using an epitaxial AlN piezoelectric layer directly grown on a conductive SiC cavity substrate with no metal layer insertion. The small impedance mismatch was verified from the variation in the free spectral range (FSR), which is comparable to the best value in previously reported HBARs.…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsAcoustic Wave Resonator Technologies · Ultrasonics and Acoustic Wave Propagation · Ferroelectric and Piezoelectric Materials
