Simultaneous high-Q confinement and selective direct piezoelectric excitation of flexural and extensional lateral vibrations in a silicon phononic crystal slab resonator

The complete phononic band gap (PnBG) of a phononic crystal (PnC) slab is used to efficiently and simultaneously confine both flexural and extensional (longitudinal) elastic vibrations in a resonator. The PnC structure is fabricated by etching a hexagonal (honeycomb) array of air holes in a silicon (Si) slab. Flexural and extensional acoustic modes in the structure are directly excited by a piezoelectric transducer stack fabricated directly on top of the resonant structure to excite the desiredmodes. Using a frequency sweep analysis, it is shown that themodes of the structure canbe selectively excitedbymodificationof the trans-