Preparation of c-Axis Oriented Pb(Zr, Ti)O3 Thin Films by RF-Magnetron Sputtering and their Dielectric and Piezoelectric Properties

The c-axis oriented Pb(Zr, Ti)O3 (PZT) thin films, which have a tetragonal structure and a composition near the morphotropic phase boundary, have been obtained on (100)MgO substrates with (100)Pt electrodes by rf-magnetron sputtering. These PZT thin films have a remarkably low relative dielectric constant of 240. The intrinsic piezoelectric and mechanical properties of the thin films were evaluated. The velocity of sound and the mechanical compliance s 11 E were measured by the piezoelectric resonance of the cantilever. The piezoelectric coefficient d 31 was measured directly from the transverse expansion of the cantilever beams. Even without a poling treatment, d 31 of the PZT thin films was -100 pC/N and almost the same as that of bulk ceramics. The extremely large piezoelectric coefficient g 31 of -57×10-3 Vm/N was also estimated because of the large d 31 and remarkably low dielectric constant. These PZT thin films are suitable for micro sensor and actuator applications.