Strain Enhancement within Cantilevered, Piezoelectric MEMS Energy Scavenging Devices

We present the current status of cantilevered MEMS vibrational energy harvesting devices with sol-gel-derived lead zirconate titanate (PZT) as the active layer. Sol-gel-deposited PZT typically suffers from lower piezoelectric constants than those from other deposition methods, but it remains a simple method for depositing PZT films onto arbitrary wafer sizes and is a scalable process. Several different cantilever geometries are explored in order to improve power output by increasing the fraction of the material strained during deflection. Finite element analysis estimates of the mechanical strain within these cantilevers, when driven at resonance, demonstrate that choice of cantilever shape can significantly affect their power output.