High Q surface acoustic wave resonators in 2–3 GHz range using ScAlN/single crystalline diamond structure

This paper describes application of the ScAlN/single crystalline diamond (SCD) structure to wideband surface acoustic wave (SAW) devices operating in 2–3 GHz range. First, it is shown theoretically that large velocity V and large electromechanical coupling factor K
²
are simultaneously achievable for the Sezawa mode existing in the structure. Next, a SAW delay line is fabricated on the structure, and it is shown experimentally that the structure offers large V and K
²
as theoretically expected, and the structure possesses very small SAW attenuation even in 3 GHz range. Finally, one-port SAW resonators are fabricated on the structure, and it is shown that wideband and high Q SAW devices are realizable in a few GHz range using the structure.