Sub-1mm² High Detection Capability PMUTS-on-CMOS Array for Ultrasound Images

This paper presents an annular multi-element piezoelectric micromachined ultrasonic transducer (PMUT) array fabricated monolithically over a 130 nm complementary metal oxide semiconductor (CMOS) analog front-end circuitry that offers an interesting solution in terms of resolution and area for IVUS catheters. The PMUT-on-CMOS array consists of five concentric rings formed of several elements with a total area less than 1 mm ² where each single element is a square AlScN PMUT with 40 μm side. The high levels of transmit pressure (28.3 kPa pp ·mm) and receive sensitivity (691.5 mV/MPa) in water at 8.6 MHz allow the detection of targets in the far-field region with dimensions below 100 μm. Demonstrations of ultrasound images in water are provided by using five wires of different diameters and materials.