Crystallization of amorphous (Ba, Sr)TiO3/MgO(001) thin films

The crystallization of amorphous BaxSr1−xTiO3 (BST) thin films was studied in a synchrotron x-ray scattering experiment. In a 550 Å thick film, the crystallization to perovskite phase was occurred at around 700 °C, while a 5500 Å thick film became crystalline at 500 °C. The thickness dependence of the crystallization was attributed to the observed intermediate phase nucleated near 600 °C at the interface. In thin films, high annealing temperature was required due to the energy barrier between the perovskite phase and the intermediate phase. In the thick film, the perovskite phase was nucleated directly from the amorphous phase in the bulk of the film concurrent to the nucleation of the intermediate phase at the interface.