Effect of the substrates on mechanical and electrical properties of Pb(Zr0.52Ti0.48)O3 thin films for MEMS applications

PZT films were deposited by a sol-gel method on platinized silicon substrates with different types of layer materials, such as silicon nitride and silicon oxide. The crystallographic orientations of the PZT films were controlled by combined parameters of a chelating agent and pyrolysis temperature. A nanoindentation CSM (continuous stiffness measurement) technique was utilized to characterize the mechanical properties of these PZT films. It was observed that (001/100)-oriented films show higher Young´s modulus compared with mixed (110) and (111)-oriented films on both SiO₂-based and SiN_x-based substrates. The influence of substrates on the mechanical properties of PZT thin films was also characterized and the results obtained from PZT thin film with SiN_x-based substrate indicated the real orientation effect. Finally, no significant influence of the film thickness was found on the mechanical and electrical properties of films thicker than 200 nm.