Study of a piezoelectric SAW resonator based on AIScN/Sapphire structure

Abstract

The objective of this work was to study the effect of the Scandium concentration (Sc) on the acoustic losses in a SAW resonator based on the Al1-xScxN/Sapphire structure at different Sc concentrations (12.5%, 25% and 37.5%). We started by studying the mechanical and piezoelectric properties of pure AlN and doped with Scandium structures, using the functional density technique (DFT). The effect of Scandium concentration on COM parameters (acoustic speed, reflectivity, transduction coefficient and static capacity) was studied. The results obtained showed that the Al1-xScxN structure is characterized by a higher piezoelectric response than those of pure AlN. The frequency analysis of IDT/Al1-xScxN/Saphir SAW delay line showed that the lower insertion loss predicted from the high Sc concentration. The resonant frequency also shifted slightly to the lower frequencies with increasing scandium concentration.