Monolithic Fabrication of Micron-Scale Piezo-Polymer Transducers on CMOS

There is growing interest in integrating piezoelectric materials with CMOS technology to enable a wide range of bioelectronic applications-including data telemetry, medical ultrasound imaging and energy harvesting. However, current integration methods face challenges in continued technology scaling and miniturazation. In this work, we present a scalable approach to integrating miniaturized arrays of ultrasound transducers - based on polymer piezoelectrics - directly onto individual CMOS die as part of an advanced fabrication and packaging flow. The on-CMOS piezoelectric transducers fabricated in this manner are more than two orders of magnitude smaller than the current state-of-the-art. We demonstrate our miniaturized transducer array in the context of both in-vitro and in-vivo photoacoustic imaging.