Possibility of BaTiO3 thin films prepared on Cu substrates for embedded decoupling capacitors by an aerosol deposition method

BaTiO3 thin films were fabricated on Cu substrates at room temperature employing an aerosol deposition method (ADM) for embedded decoupling capacitors with high capacitance densities in the thickness range of 12 to 0.2 mu m. From the thickness dependence of their dielectric properties, it was confirmed that BaTiO3 thin films acted like conductors due to high leakage currents or as dielectrics in near a thickness of 1.0 mu m. In this thickness range, we suggest that their high leakage current densities resulted from defects in the BaTiO3 thin films. Through SEM observation, it was determined that the high leakage current densities of BaTiO3 thin films were caused by defects such as pores, craters and weakly bonded areas due to large particles and agglomerated particles. To reconfirm the non-uniformity of the thin film due to defects, we reduced the diameter of the upper electrodes from 1.5 to 0.33 mm. As a result, the dielectric properties of BaTiO3 thin films with upper electrodes of 0.33 mm in diameter could be measured first in a thickness of 0.5 lam. The relative permittivity, loss tangent and capacitance densities were approximately 66, 0.026 and 114 nF/cm(2) at 10 kHz, respectively. Therefore, the possibility of thin films for embedded decoupling capacitors with high capacitance density through an ADM process may be proposed.