Hybrid AlN PZT PiezoMEMS PDK

Piezoelectric microelectromechanical systems (pMEMS) hold great promise for applications such as biomedical devices, remote sensing, and tunable photonic integrated circuits. Radiant Technologies foundry is one of the few domestic foundries for small batch thin film lead zirconate titanate (PZT) pMEMS. The primary objective of this project is to generate a robust process to fabricate PZT and aluminum nitride (AlN) piezoelectric capacitors on the same substrate.  For tunable photonic integrated circuit applications PZT capacitors can generate large strains with small voltage biases but are limited to frequencies below a few MHz. AlN capacitors require larger biases for operation, but can respond to GHz signals. By integrating the two, we will enable hybrid AlN/PZT devices for applications such as photonic integrated circuits yielding DC to GHz tuning performance on a single chip. This project will also provide incremental improvements on the existing Radiant PZT piezoMEMS PDK. Characterization of electrical parasitics will improve the ability of designers to model their devices. Thicker metal mechanical support layers will form more robust piezoMEMS better able to interact directly with larger real-world forces. Quantifying the forming gas anneal resistance of our PZT encapsulation will enable PZT piezoMEMS to be integrated with silicon devices. Adding multiple active layers to our PZT devices will enable more densely integrated sense and actuation capacitors or dual actuated devices with “push-pull” operation. Lastly, we will integrate strontium ruthenate oxide electrode layers to increase fatigue and imprint resistance of PZT piezoMEMS in high frequency/long lifetime applications.