Preparation of BaxSr1−xTiO3 thin films on TiN/Si by a novel hydrothermal-galvanic couple method

Ba_xSr_1-xTiO₃(BST) thin films have been prepared on TiN/Si by a novel hydrothermal-galvanic couple method at temperatures below 100°C. The TiN/Si specimens were immersed in Ba(CH₃COO)₂, Sr(CH₃COO)₂, and NaOH alkaline solutions with different concentration ratio. X-ray diffraction results show that cubic BST films were successfully formed on TiN/Si substrates by the hydrothermal-galvanic couple method. The growth rate of crystalline BST using the hydrothermal-galvanic couple method is much faster than the conventional hydrothermal method. The composition of BST thin films derived by the hydrothermal-galvanic couple method depends on the concentration ratio of Ba(CH₃COO)₂ and Sr(CH₃COO)₂. Field-emission scanning electron microscopy reveals spherical-particulate microstructure of BST films. The microstructure and crystalline of BST depend on the concentration of Ba²⁺ and Sr²⁺ in the solutions. Influences of Ba/Sr ratios on the growth behavior of BST films are investigated.