Material constants extraction for AlScN thin films using a dual mode baw resonator

Dual mode bulk acoustic wave resonators were fabricated using tilted c-axis oriented grains. In this case, longitudinal and shear modes are excited at the same time. The stiffness matrix for the tilted geometry was derived, and served to determine c
33
and c
44
from the two basic resonance frequencies. In addition, it was possible to estimate the tilting angle from the ratio of the sound velocities.