Multilayer Thin-film Synthesis of Ba_xSr_1-xTiO_3 Precursor and Post-annealing Processes for Final Phases

Multilayer thin-films BaxSr1-xTiO3 precursors (TiO2, BaCO3, SrCO3) were deposited on Si (100) substrate by Ar+ ion beam sputtering layer by layer sequentially. The as-deposited films were post-annealed via two steps: diffusion at lower temperature and crystallization at higher temperature, in order to convert the multiplayer precursors into final phase of BaxSr1-xTiO3. Auger Electronic Spectrum (AES) concentration depth profiles were used to study the films' diffusion through sequential precursor layers heat-treated at different temperatures, for varied holding time, and in the changed order of layer deposition. The results showed that both a long period of low-temperature and a short term of middle-temperature annealing were useful for the proper diffusion of the multiplayer precursors, and uniformly distributed compositions. The resultant BaxSr1-xTiO3 conld be crystallized at 900℃ from the fully annealed precursors.