Thin-Film Lithium Niobate Based Piezoelectric Micromachined Ultrasound Transducers

This work presents the first thin-film lithium niobate (LiNbO3) based piezoelectric micromachined ultrasound transducers (PMUT). Efficient flexural mode excitation is achieved using a proposed lateral field excited (LFE) structure. Thanks to the significant piezoelectricity and low loss in LiNbO3, the implemented device shows an out-of-plane mode at 7.6 MHz, with high electromechanical coupling of 4.2%. The measured Q in vacuum is 2605 indicating the low structural loss, while the measured Q in air is 264 suggesting the ultrasound radiation. Upon further optimizations, LiNbO3-based PMUTs are promising candidates for miniature ultrasound applications.