Fabrication And Characterization Of A MEMS Bistable In-Plane Actuator Based On Antiferroelectric Film

Under the electric field, the inside lattice of antiferroelectric films’phase changes, which leads to the volume changes of antiferroelectric films, resulting in a greater nonlinear bistable distortion, and the time of phase transition is very short. Based on the antiferroelectric films phase transition’s fast response and nonlinear bistable strain characteristic, combing with micro-electromechanical systems (MEMS) process, the integrated manufacturing of antiferroelectric films and silicon micro-devices can be achieved. And this has a wide prospect on large displacement, fast response and bistable MEMS switches and digital displacement type bistable MEMS actuator and other fields. In this paper, the Preparation, performance and phase transition behavior and of (Pb0.97La0.02)(Zr0.9Sn0.05Ti0.05)O3(PLZST) antiferroelectric films were studied in details, and combing with MEMS technology, the designation and production of antiferroelectric bistable MEMS surface actuator were completed. Finally, the motion performance of drive was studied and analyzed.Fisrt, LaNiO3(LNO) was successfully prepared by Magnetron Sputtering method on Si substrate. Electrical test results shows that the resistivity of LNO film is about 2mΩ·cm. It is suitable to be used as electrode material because of its good electrical conductivity. Then, PLZST films were successfully prepared by Sol-Gel method on LNO/Si substrate, X-ray diffraction (XRD) analysis shows that PLZST films were of perovskite structure with good crystallization. Scanning electron microscope (SEM) images showed that the surface of PLZST films were smooth, fine-grained and crack-free. The test results of antiferroelectric properties shows that, the electric field induced curves of PLZST antiferroelectric thin film are all double ferroelectric hysteresis loops, thus antiferroelectric property is good. The PLZST AFE films with different thickness had been prepared on LNO/Si substrates by a Sol-Gel method. The XRD results show that all the PLZST films are (120)-oriented perovskite structures. The remnant polarization and dielectric constant decrease while the energy storage density increases with the film thickness increases. It is suggested that AFE and FE phases coexist in the films. The content of FE phase decreases while The content of AFE phase increases with the film thickness increases due to the released internal compressive stress induced by the restraint of the LNO film.Combing with MEMS processing technology, and studying the photo etching technology of PLZST/LNO films, the antiferroelectric film MEMS actuator was manufactured. Finally, Based on laser Doppler vibrometer and Stroboflash, out-of-plane and in-palne motion performance of PLZST and PNZT MEMS actuator were tested. In the last, a step, voltage driving and non-linear nature of the bistable in-plane displacement and linear in-plane displacement were realized.