Hybrid powder-sol–gel PZT thick films on metallic membranes for piezoelectric applications

A hybrid sol–gel-powder method was used to process 3–6 μm thick lead zirconate titanate films via spin-coating a Ni-base alloy and silicon substrates. The films were crack free and possessed a fine microstructure. High effective piezoelectric coefficients, d33, of 250 pm/V were obtained from piezoelectric hysteresis loops using a laser vibrometer. Crack free sensor membranes were obtained from these film heterostructures via laser beam micromachining, and their resonance behaviour was studied. Metallic membranes showed the best characteristics where deflections of up to 120 nm at resonance could be obtained at an excitation voltage amplitude of 0.5 V. Characterization of the membranes in terms of output current and voltage was also performed, and show the suitability of such heterostructures for piezoelectric sensor applications.