Low-loss GHz frequency phononic integrated circuits in Gallium Nitride for compact radio-frequency acoustic wave devices
arXiv:2305.16961 · doi:10.1109/TUFFC.2023.3332146
Abstract
Guiding and manipulating GHz frequency acoustic waves in m-scale waveguides and resonators opens up new degrees of freedom to manipulate radio frequency (RF) signals in chip-scale platforms. A critical requirement for enabling high-performance devices is the demonstration of low acoustic dissipation in these highly confined geometries. In this work, we show that gallium nitride (GaN) on silicon carbide (SiC) supports low-loss acoustics by demonstrating acoustic microring resonators with frequency-quality factor () products approaching Hz at 3.4 GHz. The low dissipation measured exceeds the bound set by the simplified isotropic Akhiezer material damping limit of GaN. We use this low-loss acoustics platform to demonstrate spiral delay lines with on-chip RF delays exceeding 2.5 s, corresponding to an equivalent electromagnetic delay of 750 m. Given GaN is a well-established semiconductor with high electron mobility, our work opens up the prospect of engineering traveling wave acoustoelectric interactions in m-scale waveguide geometries, with associated implications for chip-scale RF signal processing.
10 pages, 9 figures. Comments welcome !!!