Characterization of acoustic vibration modes at GHz frequencies in bulk acoustic wave resonators by combination of scanning laser interferometry and scanning acoustic force microscopy

The application of scanning laser interferometry (SLI) and scanning acoustic force microscopy (SAFM) for the characterization of acoustic vibrations at GHz frequencies in RF resonators is combined and discussed in this work. As a model example, the characterization of a film bulk acoustic resonator (FBAR), including vibration amplitude mapping, decomposition of vibration images into acoustic modes, mode shape reconstruction, dynamic visualization of acoustic vibrations and measurement of dispersion curves, is accomplished by the combination of both techniques.