GaN-on-SiC Surface Acoustic Wave Devices Up to 14.3 GHz

This work presents the first investigation of the SweGaN QuanFINE® ultrathin GaN-on-SiC platform for the performance of surface acoustic wave (SAW) devices over 14 GHz. Frequency scaling is made possible by the absence of a thick buffer layer typical in epitaxial GaN technology. After finite element analysis (FEA) simulation to identify acoustic modes, SAW devices were designed, fabricated, and characterized. Measurements from one-port interdigital transducers (IDTs), two-port delay lines, and one-port resonators were fitted with modified Mason and Butterworth-Van-Dyke (BVD) models. Extracted piezoelectric coupling coefficient (k
²
) matches well with simulation for the IDTs with the highest value of 0.53% at 11.1 GHz. Maximum Q
m
of 542 and
$f$
. Q
m
product of 6×10
¹²
are achieved for the resonators at the same frequency with a propagation loss of 0.08dB/λ. Sezawa modes up to 14.3 GHz are observed, a record high in GaN MEMS to the best of the authors' knowledge.