Design and technology for uniform aluminum nitride piezoelectric micromachined ultrasonic transducers with radial array

This paper reports on design, technology and mechanical characterization in air of a piezoelectric aluminum nitride (AlN) based micromachined ultrasonic transducer (PMUT) with six radial symmetric arrays. The PMUT consists of 4018 single membranes with a resonance frequency of 3.4 MHz, a quasi-static deflection of 272 pm/V and a resonant deflection of up to 71.3 nm/V. The small standard deviation of the resonance frequency over the chip is 47 kHz.