Technology for Piezoelectric Micromachined Ultrasonic Transducers with Adaptive Channel Geometry and Chip Size

This paper presents the design, technology and the characterization of Aluminum Nitride (AIN) based Piezoelectric Micromachined Ultrasonic Transducers (PMUTs). The PMUTs chips have an overall chip size of 10 x 10 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with 100 smaller cells including multiple circular membranes for generating acoustic signals up to 172 dB SPL per mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> chip size and per actuation voltage at 10 mm distance at 1.7 MHz. The novel aspect of this work lies within the development and special design provisions of the chip wherein the number of channels, channel geometry and its size can be adapted as per the requirement just by altering the wire bonds.