Thickness dependence of dielectric properties in BaTiO3 films fabricated by aerosol deposition method

In order to prepare embedded planar decoupling capacitors with high capacitance density, we attempted to fabricate BaTiO3 thin films on Cu substrates at room temperature by employing aerosol deposition method (ADM). Their thickness range was 0.2–1.5 μm. From the measurement of the magnitude and phase of their impedance by a vertical type, it was confirmed that BaTiO3 thin films acted like conductors or dielectrics in the thickness range of 0.8–1.0 μm. In this thickness range, we supposed that their high leakage currents resulted in the problems of interfaces between BaTiO3 thin films and Cu substrates or the quality of BaTiO3 films themselves. So, the magnitude and phase of impedance of BaTiO3 thin films deposited on glass substrates and Cu substrates to remove the problems of interfaces were measured by a horizontal type. As a result, all BaTiO3 thin films deposited on glass substrates became dielectrics. However, some BaTiO3 thin films with below 0.8 μm deposited on Cu substrates acted like conductors in this thickness range. Consequently, it could be suggested that the major causes were problems of interfaces between BaTiO3 thin films and Cu substrates.