Displacement Extraction of Piezoelectric Films

Piezoelectric-based innovative components and architectures depend on the strong interactions between their mechanical and electrical materials properties. Such type of materials requires a polling step to activate their piezoelectricity. Before the polling and with the application of electric fields to piezoelectric material across its thickness, only the dielectric constant will change, while after polling the piezoelectric materials mechanically extracts and/or contracts in addition to the change in dielectric constant. This work reports for the extraction of vertical piezoelectric film displacement coupling electromagnetics simulations with capacitance-voltage measurements. An interdigital capacitor structure has been fabricated and used as demonstrator. Lead zirconate titanate thin film of 0.75μm thickness with known properties has been used as piezoelectric film materials. The device capacitance-voltage measurements have been conducted at different DC biasing voltages using LCR impedance analyzer. The electromagnetic simulations have been carried out using Sonnet EM-simulator. The capacitance-spacing curves for different dielectric constants values were generated out of these electromagnetic simulations. Curve fitting technique is used to establish the connecting equation between the measured capacitance and spacing at specific applied voltage.