Preparation of highly c-axis oriented Sr_0.6Ba_0.4Nb₂O₆thin films grown on Silicon substrate by the sol-gel process

Ferroelectric strontium barium niobate (Sr0.6Ba0.4Nb2O6) thin films have been prepared on p-type Si (1 0 0) substrates using sol-gel process. The micro-structure and crystalline phase were studied by X-ray diffractometry, transmission electron microscopy and Raman microprobe spectroscopy. It is found that the SBN films performed a highly c-axis preferred orientation perpendicular to the Si substrates. The preferred orientation is demonstrated to be closely related to the existence of the potassium ions which were not be filtered out completely during the preparation of the niobium alkoxide. High post-annealing temperature results in inter-diffusion of the potassium ions, strontium ions, barium ions and silicon ions, which can create an amorphous layer between the SBN film and the Si substrate. However, the amorphous layer can adjust the large lattice mismatch between the film and substrate and serves as a buffer layer for the highly c-axis orientated SBN films.