Investigation of dielectric properties of BaTiO3 films doped with Sr, Gd, Co, Zr and Mn elements with spin coating method

In this study, BaTiO3, Sr:BaTiO3, Gd:BaTiO3, Co:BaTiO3, Zr: BaTiO3 and Mn:BaTiO3 solutions were prepared by sol-gel method. The prepared solutions were coated with 3, 5 and 7 times on the substrates which were cleaned 15 minutes each in ultrasonic bath with ethanol, distilled water and acetone, respectively. Thin films which were coated on glass substrates were heat-treated for 1 hour in a tube furnace heated to 400 oC at the rate of 5◦C/min. After heat treatment, thin films were analyzed by Scanning Electron Microscope, Polarized Light Microscope and Atomic Force Microscope. Subsequently, X-ray diffractometer was used to determine the formation of crystal structure. The dielectric constants of the prepared undoped and doped BaTiO3 thin films were measured in a 3-7 GHz frequency range via a Vector Network Analyzer. As a result of the study, crystal structure formation was not observed in films which were dried at 400 oC. However, some of the films that were heat treated at 550 oC had a crystal structure. After coating, the highest dielectric constant among the coated thin films without drying was measured on Zr doped BaTiO3 thin film with the value of 9.4 at 6.8 GHz. The highest dielectric constant value obtained in the measurement after drying at 400 oC was determined as 7.7 in Sr doped BaTiO3 thin film.