Microstructure Design And Performance Analysis Of PMNT Thin Films Prepared By Magnetron Sputtering

With the continuous development of integrated ferroelectric technology,the integration and miniaturization of ferroelectric thin film devices have become a hot topic.Compared to ferroelectric ceramic devices and single crystal ferroelectric devices,Ferroelectric thin film devices not only respond fast,high sensitivity but also compatible with the integrated circuit.It is easy to miniaturization and array.Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃?PMN-PT,PMNT?has become one of the preferred materials for ferroelectric devices due to its high pyroelectric coefficient,high dielectric constant and low dielectric loss.Due to the preparation of high temperature,remove pyrochlore phase and control the crystal orientation difficultly,PMNT thin film can not be widely used in ferroelectric devices.In view of the obove problem,preparing technologies,photolithography of structural units,structures and electric properties of PMN-PT ferroelectric thin films were studied in this thesis.Materials performance of thin film:Experiments need PMNT thin film structure unit to test the electrical performance.PMNT thin film structure unit has many layers,Such as TiO₂ buffer layer,Pt bottom electrode layer,LSCO epitaxial layer,PMNT ferroelectric thin film,Ni Cr absorber layer and Au upper electrode layer,The effects of substrate temperature,rapid heat treatment and atmosphere on the material properties and electrical properties of PMNT thin films prapared by magnetron sputtering were investigated.The main conclusions are as follows:?1?LSCO epitaxial layer not only has good conductivity,but also can control the orientation of PMNT thin film.Ar/O₂ flow ratio and substrate temperature of LSCO thin film are 16:4 and 575?,LSCO thin film resitivity is about 1.45×10^-5?·cm,Witch is similar to the resistivity measured by Pt bottom electrode of 1.35×10^-5?·cm.At this point,the film is distinct?100?orientation.?2?PMNT material properties are effected by the annealing conditions,the substrate temperature,epitaxial layer and other factors.When epitaxial layer,growth temperature,annealing temperature and annealing time are LSCO,500?,600?,10min The SEM test of PMN-0.3PT thin film is relatively uniform and compact microstructure.The XRD test result is pure perovskite structure with?100?orientation.Unit preparation and electrical preformance?1?The structure unit was prepared by lithography technique,and the smallest line width of the structural unit was used as the experimental object.Experimental studies AZ-5214photoresist lithography process,exposure time,bake time,developing time are 13s,120s and90s,The electrode line is clear and exposure area is developed completely.?2?The electrical properties of PMNT films,such as ferroelectric,dielectric and leakage characteristics are affected by annealing factors.Higher residual polarization,smaller leakage current,higher dielectric constant and smaller dielectric loss of PMNT thin film can be abtained after annealed.The experimental results show that the dielectric constant of the film after annealed is 230,the dielectric loss is 0.05 and the remanent polarization is 16uC/cm².