Enhanced piezoelectric and imprint characteristics of in situ sputtered Ta-doped Pb(Zr,Ti)O₃ thin films on Ir/TiW/SiO₂/Si substrates

High quality piezoelectric thin films have been pursued with simpler processing steps without subsequent annealing and poling procedure. Here, the in situ domain formation process of Ta-doped Pb(Zr_0.52Ti_0.48)O₃ thin films was experimentally verified when the sputtering deposition proceeded with nonconventional buffer electrodes of Ir/TiW. The 2 mol% Ta-doped thin films with ∼2 μm thickness showed promising transverse piezoelectric coefficient e₃₁ of −8.66 C/m² and enhanced imprint behavior with a coercive field shift E_c,shift of ∼24 kV/cm. These improvements, which are ideally useful for mobile sensor applications, are attributed to the increase in crystallinity and the preferred domain orientation induced by the in situ polarization upon deposition. The incorporation of Ta into the perovskite lattices as a donor seems to help in inducing stronger internal field in the film by forming defects-driven dipoles. Therefore, this internal field might cause a clamping of domain walls, leading to the strong imprint behavior.