Imaging of acoustic fields in bulk acoustic-wave thin-film resonators

By using an atomic-force-microscope-based technique, we image the vibration of high-frequency, bulk-mode, thin-film resonators. Our experimental technique is capable of monitoring the vibration of these devices over a broad frequency range, from 1 MHz to beyond 10 GHz, allowing us to obtain quantitative measurements of the piezoelectric properties of thin-film materials in that frequency range. This technique allows us to map the complex vibration modes of a new generation of high-frequency bulk piezoelectric resonators, revealing the presence of vibration patterns of very different characteristic lengths.