Preparation and application of lead zirconate titanate (PZT) films deposited by hybrid process: Sol-gel method and laser ablation

Among the many ferroelectric film fabrication techniques, the sol-gel process provides high purity, large deposition area and easy composition control. However, the thickness limit of a crack-free single-layer film is about 0.2 mum and about 10 times of coating and thermal treatment processing are needed to deposit 1.5 mum-thick films. In laser ablation, the deposition rate is expected to be 1-2 mum/h, but the film quality is lower than that deposited by the sol-gel method. In this work, the hybrid process, involving the sol-gel method and laser ablation, was used to make 1.65 mum-thick lead zirconate titanate (PZT) films with well-crystallized perovskite phase at the (111) orientation. We deposited (111)-oriented 0.15 mum-thick PZT film on Pt/Ti/SiO2/Si substrates using the sol-gel method and then deposited 1.5 mum-thick PZT films by laser ablation. The remanent polarization of 28.6 muC/cm(2) and the coercive field of 58.0 kV/cm were obtained while the dielectric constant and loss values measured at 1 kHz were approximately 1050 and 0.045, respectively. The piezoelectric coefficient d(31) was also investigated and found to be 16.65 +/- 4 pC/N. In the application, a micromirror actuated by the hybrid PZT films was designed and fabricated successfully by a three-mask lithography process. The scanning angle of 6 2 degrees was demonstrated, while resonating with 5 V-p.p at the resonance frequency (1975 Hz).