Longitudinal Displacement Measurement of Lead Zirconate Titanate Thick Films Deposited on Silicon substrates

10-μm-thick PZT films were deposited on the Pt/Ti/SiO₂/Si substrates, and 20- to 500-μm-diameter PZT thick film disks on the Si substrate were fabricated. The butterfly shape displacement curves of the top side, bottom side and subtraction of bottom side from top side were measured with twin-beam interferometer, and the effect of the disk diameter on these displacements were compared with FEM simulation. The clamping effect is eliminated when the ratio of the PZT disk diameter, d, to the PZT film thickness, t, is less than three, that is d/t ≪ 3, for 10-μm-thick PZT film. Therefore, the actual longitudinal displacement of the PZT films can be evaluated for d/t ≪ 3.