A 0.5 mm2 pitch-matched AlN PMUT-on-CMOS ultrasound imaging system

This paper presents a 0.5 mm
²
pitch-matched array based on 7x7 AlN piezoelectric micromachined ultrasonic transducers (PMUTs) monolithically integrated with its 130 nm complementary metal oxide semiconductor (CMOS) analog front-end circuitry. The transmission side is composed of three high voltage CMOS Pulsers while the readout is only carried out at the central row by a CMOS Low Noise Amplifier. The acoustic characterization in a liquid environment gives competitive transmitting and receiving sensitivities with values of 22 kPa*mm and 2.9 V/MPa, respectively. The PMUT-on-CMOS potentiality for ultrasound imaging was validated using a manual scanning of an earring placed at 2 mm, resulting in a dynamic range of 12 dB and solving details of 300 µm width.