Structure and dielectric properties of Sr and Zr doped BaTiO3 thin films prepared by solution deposition technique

According to different behavior in dependence of temperature, perovskites are recognized as good candidate for a broad range of applications in microelectronic industry. Barium titanate is one of the most important... [ view full abstract ]

According to different behavior in dependence of temperature, perovskites are recognized as good candidate for a broad range of applications in microelectronic industry. Barium titanate is one of the most important ferroelectric perovskite materials used for production of capacitors, sensors and memories. However, in last decade, paraelectric BaTiO₃ phase (above the Currie temperature) has been used for fabrication of tunable microwave devices. Most of tunable devices works at room temperature and the pure barium titanate is not suitable for their preparation. Because of that, substitution of Ba²⁺ and/or Ti⁴⁺ with different cations is useful strategy to decrease the Currie temperature around room temperature and achieve paraelectric phase.

In this work influence of strontium and zirconium addition on structure and properties of barium titanate nanocrystalline thin films was investigated. Clear solutions of Ba_1-xSr_xTiO₃ (x=0.1, 0.2, 0.3, 0.4) and BaTi_1-xZr_xO₃ (x=0.1, 0.2) were prepared by sol gel method. The obtained solutions were deposited on platinized silicon substrates by spin coating method and finally sintered up to 1000 °C. Changes in structure and electric properties of the doped films in dependence of the dopant concentration and sintering temperature were examined by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, dielectric measurements, etc. Designing of electrodes for tunable measurements was also investigated and different techniques such as lithography and inkjet printing were examined in order to obtain desirable architectures.