Structural Control And Property Study Of Barium Titanate Ferroelectric Films

With the development of science and technology,the demand for materials with special properties is increasing.Barium titanate（Ba TiO₃,BTO）is one of the earliest discovered perovskite-type ferroelectric materials with octahedral structure,possessing various properties such as dielectric,ferroelectric,nonlinear optical,pyroelectric,and piezoelectric,making it an important functional thin film material.However,most ferroelectric thin films currently are single-component polycrystalline structures,with weak remanent polarization and poor electrical properties,and with weak interface regulation,unable to perform component regulation,which severely restricts the exploration of their properties and efficient applications.This article aims to explore the preparation and performance regulation of BTO ferroelectric thin films,as well as their prospects for application in the field of electronic functional ceramics,contributing to the performance optimization of perovskite-type（ABO₃）ferroelectric thin films and miniaturization and integration of electronic components.A series of BTO films were prepared on Si substrates using magnetron sputtering technology,and the influence of the thickness,material,and structure of the bottom electrode buffer layer on the BTO film was mainly studied,as follows:（1）Explore the preparation process of BTO films and strontium ruthenate（SrRuO₃,SRO）bottom electrode.BTO films and SRO bottom electrodes at different temperatures were prepared on single-crystal Si.XRD spectra showed that the BTO film crystallized best at 700℃,and SRO had the best crystallinity at 600℃.（2）Based on the optimized film preparation process,the influence of SRO bottom electrode thickness on the performance of BTO films was explored.It was found that the BTO film grown on SRO（600 nm）bottom electrode had the largest dielectric constant,and its saturation polarization strength was also the largest,reaching 20.41μC/cm² at the same applied voltage of 60 V.In addition,the BTO film on SRO（400 nm）had the largest total energy density,while the BTO grown on the 600nm SRO had the largest recoverable energy density.（3）Explore the effect of different bottom electrodes SRO,lanthanum nickel oxide（LaNiO₃,LNO）,and indium tin oxide（ITO）on BTO films.The BTO/SRO film had a（111）preferred orientation,while the BTO grown on LNO and ITO bottom electrodes were polycrystalline.The BTO/SRO had the largest grain size and dielectric constant,and the recoverable energy storage density of BTO/LNO was the largest,reaching 53.12 J/cm³ at an external voltage of 60 V,while the BTO/ITO film had a large leakage current and almost no ferroelectric properties.The BTO/LNO film had the smallest grain size and good voltage resistance.Finally,the jump voltage and high-to-low resistance ratio of Au/BTO/SRO and Au/BTO/LNO capacitors were studied,and it was found that the Au/BTO/SRO capacitor required less energy consumption to reach the jump point,while the high-to-low resistance ratio of the Au/BTO/LNO capacitor could reach 500.（4）Based on the above research,the influence of three different composite electrodes SRO/LNO,LNO/SRO,and LNO/Zn O on BTO films was explored.The structure and performance characterization analysis showed that the BTO/SRO/LNO film exhibited a polycrystalline structure,with a larger dielectric constant and better voltage resistance than the BTO/LNO film.At an external voltage of 30 V,the energy storage efficiency could reach 95.33%.The BTO/LNO/SRO film showed a（00l）preferred orientation,with smaller dielectric loss than the BTO/SRO film.At an external voltage of 120 V,the recoverable energy storage density Wrec could reach 73.22 J/cm³,and the energy storage efficiency could reach 92.37%at an external voltage of 60 V.The BTO/LNO/Zn O film showed a（00l）preferred orientation,with a larger dielectric constant than the BTO/LNO film,up to770（1 MHz）.The BTO/LNO/Zn O film had good voltage resistance,maintaining a good ferroelectric hysteresis loop at 350 V.In addition,the energy storage efficiency of the BTO/LNO/Zn O film could reach 93.52%at an external voltage of 50 V,and the recoverable energy storage density could reach293.32 J/cm³ at an external voltage of 350 V.