Thin Film Piezoelectric Aluminum Nitride for Piezoelectric Micromachined Ultrasonic Transducers

Piezoelectric aluminum nitride (AlN) thin film based piezoelectric micromachined ultrasonic transducers (PMUTs) are processed on 150 mm wafer diameter technology. The 300μm and 500 μm diameter membranes are arranged in a 3 by 3 array per chip. The membranes are actuated in resonance in air for characterization. The PMUTs deflection is 1250 nm/V at 164.7 kHz for small signal actuation. For 1 V AC actuation the deflection in air is 530 nm/V, The relative change of impedance in resonance is 9.8 %.