Study On Modification Methods Of PZT Thin Films And Its Application In Microactuators

The PZT thin films were fabricated by sol-gel process in this paper.The modification methods of PZT films and its application in microactuators were studied.The crystal orientation,microstructure,dielectric,ferroelectric properties,fatigue resistance and vibration properties of modified PZT thin films were characterized.The influence of buffer layer and doping on the growth of PZT films were considered to discuss mechanisms of guiding growth of buffer layer and doping modification.The following sections were included in this paper.?1?The effects of PbTiO₃ buffer layer and PZT buffer layer with different lead content on the growth of PZT thin films were studied.The PZT thin films spin-coated on PbTiO₃ buffer layer were prepared and characterized.The results show that PbTiO₃ buffer layer with?100?preferred orientation guides growth of PZT films along?100?orientation,enhances the?100?peak intensity and is favorable for PZT films to form dense columnar perovskite structure.The dielectric constant and loss tangent of PZT films were increased by introducing PbTiO₃ buffer layer.The PZT thin films spin-coated on PZT buffer layer with different lead content were prepared and characterized.The results show that all films exhibit dense perovskite structure with?100?preferential orientation.The degree of?100?preferred orientation increases as the lead content in buffer layer enhances.The PZT film with buffer layer containing 25%excess lead obtains maximum dielectric constant,which reaches 1571?100 Hz?.The maximum remnant polarization,minimum coercive field and best fatigue resistance were obtained in the PZT film with buffer layer containing 15%excess lead.?2?The effects of Nb,Nd doping on the growth of PZT thin films and the thickness of pyrolytic film on the growth of Nd-doped PZT films were studied.The PZTNb thin films with Nb doping concentration from 0%to 5%were prepared and characterized.When the Nb doping concentration is from 1%to 4%,all films are presented with dense perovskite structure with?100?preferred orientation.2%Nb-doped PZT film obtains maximum?100?preferred orientation degree,which reaches 80.3%.The grain size is largest in 4%Nb-doped PZT film,which obtained maximum dielectric constant,reaching1412.5?100 Hz?and increased by 46.9%than undoped film.When the Nb doping concentration is 2%,the fatigue resistance is improved and the maximum remnant polarization is obtained,reaching 14.5?C/cm²,an increase of 46.5%compared with undoped film.The PZTNd thin films with different Nd doping concentration and pyrolytic film thickness were prepared and characterized.The results show that PZTNd thin films with thinner pyrolytic film thickness have better crystallization behavior.The?100?peak of PZTNd films with different Nd doping concentration exhibit shifting phenomenon.As the Nd doping concentration increases,the?100?peak intensity of PZTNd films with thicker pyrolytic film thickness decreases and the grain size of PZTNd films with thinner pyrolytic film thickness increases.The best fatigue resistance is obtained in 2%Nd-doped PZT film with thinner pyrolytic film thickness,which also achieves maximum dielectric constant.The maximum remnant polarization is obtained in 1%Nd-doped PZT film with thicker pyrolytic film thickness,which reaches 20.9?C/cm²,increasing 62.0%compared with undoped film.?3?The PZT piezoelectric microactuators were fabricated by MEMS technologies and the vibration property was characterized by laser Doppler vibrometry test system.The results show that the amplitude of PZT thin films was enhanced by introducing buffer layer and doping modification.The fabiricated PZT thin films were used to drive piezoelectric inkjet printhead to eject droplets.