Monolithic Integration of Micron-scale Piezoelectric Materials with CMOS for Biomedical Applications

We present the development of micro-fabrication techniques achieving the monolithic integration of micron-scale piezoelectric ultrasonic transducers in both polyvinylidene difluoride (PVDF) and lead zirconate titanate (PZT) with complementary metal-oxide-semiconductor (CMOS) integrated circuits (ICs). PVDF-CMOS integration is driven by applications in energy harvesting and data telemetry for medical implants, while PZT-CMOS integration is applied to high-resolution two-dimensional (2D) ultrasound imaging. Both of these applications benefit from reduced parasitic capacitances and higher levels of integration possible with monolithic CMOS integration. Characterization results of micro-fabricated devices reveal the preservation of the piezoelectric properties of PVDF and PZT and transducer functionality with co-designed CMOS ICs.