Microstructure and dielectric properties of Sr2Nb2O7 thin films by metalorganic decomposition

Sr2Nb2O7 thin film was prepared by metalorganic decomposition (MOD). Mixed Sr-Nb containing stock solution was coated onto Pt/Ti/SiO2/(100)Si and Pt/ZrO2/SiO2/(100)Si substrates using spinner, and annealed at 900-1100 degrees C in an oxidizing atmosphere. XRD patterns revealed the presence of Sr2Nb2O7 phase with no sign of any second phase. When Pt/ZrO2/SiO2/(100)Si substrate was used, strong grain orientation along [OkO] direction occurred with annealing temperature increase. Due to distributed micro-cracks at film surface, however, large leakage current on the order of 10(-4) A/cm(2) was measured for thin film capacitor annealed at 1000 degrees C given voltage stress of 25 kV/cm. Dielectric constant value at room temperature was about 22 at 10 kHz.