Title:  Acoustic Resonators based on Epitaxial AlN/AlScN Ultra-thin Piezoelectric Films

Committee:

Dr. Azadeh Ansari, ECE, Chair, Advisor

Dr. John Cressler, ECE

Dr. Farrokh Ayazi, ECE

Dr. Oliver Brand, ECE

Dr. Sukwon Choi, PSU

Abstract: This work is focused on the design, fabrication, and characterization of MEMS acoustic resonators based on Epitaxial AlN/AlScN thin piezoelectric films. This work demonstrates super high frequency(SHF) lamb, surface acoustic wave(SAW), and thin-film bulk acoustic wave resonators (FBAR) based on single-crystal orientation Alumium Scandium Nitride (AlScN) thin films grown on silicon substrates by molecular beam epitaxy (MBE). In order to target emerging wireless communication standards, such as 4G LTE/5G, the effects of film thickness on FWHM and Sc concentration on piezocoefficient are studied based on the requirements of the resonators/filters for operation at the SHF range. Furthermore, this work reports on the generation and frequency tuning of phononic(mechanical) frequency combs in an integrated standalone AlN-on-Si flexural resonator via non-degenerate parametric pumping. Cubic nonlinearity due to the geometrical Duffing effect is studied and induced various parametrically-excited regimes are presented along with stress-induced mode coupling in Aluminum Nitride (AlN) circular MEM resonators.