Strain Measurement and Mechanical Property Evolution in Sol-Gel PZT Thin Films
Cracking is a notorious issue with sol-gel PZT thin films, and film failure in this manner is difficult to reliably predict due to constantly evolving mechanical properties. In this work, two non-contact experimental methods are used to quantify the stiffness response of PZT sol-gel during thermal loading and the influence of solution additives, such as lactic acid and gycerol. The mechanical properties are determined using a digital image correlation method to measure strain and wafer curvature measurements to estimate bi-axial stress. Results show the transition from a compliant response to more glassy behavior. The importance of this changing stiffness is shown for a specific application of a buckled MEMS actuator and in relation to adhesion based failure modes.