Low-temperature crystallization and electrical properties of BST thin films using excimer laser annealing

(Ba,Sr)TiO₃ (BST) thin film with a perovskite structure has a potential for the practical applications in various functional devices. Normally, the BST thin films derived from sol-gel and sputtering are amorphous or partially crystalline when processed below 700 °C. For the purpose of integrating BST thin film directly into system-on-package (SoP), it is necessary to process the BST film below 350 °C. The electrical properties of low-temperature crystallized BST film were studied in this paper. The BST thin films have been crystallized at 300 °C by excimer laser annealing (ELA). The BST films were exhibited in a single perovskite phase and have well-defined electrical properties such as high dielectric constant, low dielectric loss and low leakage current density. As a result, we demonstrated crystallized BST thin film which has permittivity of 143, dielectric loss of 0.028 and leakage current density of 0.9 μA/cm² below 300 °C.