Role of Surface Hardness of Substrates in Growing BaTiO3 Thin Films by Aerosol Deposition Method

概要

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BaTiO3 thin films with 0.1–3.0 μm thick were grown on Cu and stainless steel (SUS) substrates at room temperature by the aerosol deposition method (ADM) to examine the role of the surface hardness of substrates in ADM as a thin film process. When Cu substrates were used, BaTiO3 thin films less than 0.5 μm thick showed electrically short characteristics mainly because the number of macroscopic defects in the films provided a direct path for leakage currents. In the case of harder SUS substrates, however, the thinner BaTiO3 films of 0.2 μm thickness exhibited dielectric properties since they had much denser microstructures without the defects and with less rough interfaces than those on Cu substrates. By comparing the microstructures depending on the surface hardness of substrates and investigating the leakage current mechanisms, it was determined that the fundamental cause of the thickness limits for dielectrics in the growth of BaTiO3 films by ADM was the roughness of interfaces between the films and substrates.
2009-09-25