RF capacitive piezoelectric displacement extraction

The piezoelectric materials exhibit strong interaction between their mechanical and electrical properties that could be translates into innovative components and architectures. This paper reports for the extraction of a piezoelectric thin film displacement when subject to voltage stress using interdigitated capacitance measurements. An interdigital structure incorporating 0.75 μm thin film lead zirconate titanate has been constructed. With bias applied between the fingers, the spacing between them will expand, therefore reducing the total capacitance. Both capacitor theory and piezoelectric material analysis are used to extract the film displacement from the measured capacitance variation.