Piezoelectric coefficients of thin film aluminum nitride characterizations using capacitance measurements

Piezoelectric materials have become very useful in MEMS devices because of their electrical-mechanical reciprocity. Aluminum nitride has attracted considerable attention in recent years owing to its unique properties. Here we report for the determination of aluminum nitride (AlN) piezoelectric thin film charge constants. When voltage is applied, the AlN film geometrical dimensions will change. The proposed technique does this determination by taking the ratio of parallel plate capacitance for two different bias conditions under set of assumptions in deriving the equations for the ratio of capacitance for the two bias conditions.