Single-Crystalline Bulk Acoustic Wave Resonators Fabricated With AlN Film Grown by a Combination of PLD and MOCVD Methods

Among the various methods that have been utilized to enhance the efficiency of Bulk Acoustic Wave (BAW) filters, the AlN piezoelectric layer quality improvement demonstrates robust functionality and operability. A combination of pulsed laser deposition (PLD) and metal–organic chemical vapor deposition (MOCVD) methods of growing III-nitride films, the MEMS wafer process based on which was then constructed to prepare the Single-crystalline AlN Bulk Acoustic Resonators (SABAR). The as-grown film has a reduced full-width at half-maximums for AlN (0002) X-ray rocking curves of 0.21°, a lower average RMS of 0.140nm, and a higher effective coupling coefficient of 6.25%, indicating a 4097 Q-factor of SABAR resonator that precedes BAWs by an incredibly 182.5% with PVD sputtered AlN.