Ultrathin barium titanate films by polyol thermal decomposition process

摘要

We have successfully fabricated barium titanate (BaTiO₃) films on Si (100) and Pt(111)/Ti/SiO₂/Si substrates using the polyol thermal decomposition (PTD) process by spin-coating technique. In PTD process, we confirmed that the crystalline oxycarbonate Ba₂Ti₂O₅CO₃ films were directly formed as a consequence of evaporation of polyol precursor solution prepared simply by mixing metal chlorides and ethylene glycol, and then converting them into crystalline BaTiO₃ films through thermal decomposition at >500 °C. This feature makes it possible to grow densely packed and crack-free BaTiO₃ films as thin as 70 Å per cycle. Although PTD is described here for a complex metal-oxide film of BaTiO₃, other simple and complex metal-oxide thin films with high-dielectric constant materials are also likely to be suitable for deposition with accurate control of film thickness and composition using the polyol precursor solutions.