Properties of multilayer ceramic capacitor with BaTiO₃ thin layers deposited by e-beam evaporation

For the purpose of enhancing the capacitance of MLCCs, thin BaTiO ₃ dielectric layers and inner electrodes were prepared by ion beam assisted e-beam evaporation method. BaTiO₃ films deposited at 300°C showed an amorphous structure and the films annealed above 550°C showed polycrystalline structure. XPS analysis showed the complete oxidation from Ti metal source to TiO or BaTiO₃ phase. The dielectric constant of 130∼ 150 and dissipation factor of 2∼4% were obtained from BaTiO ₃ of single layer. The capacitance decreased with increasing the temperature and satisfied the specification of ±15% limit at 125°C. There was only small capacitance change with DC bias voltage and after annealing of films, leakage current was 10^-8∼10^-9 A at 10 V. The overall results showed that BaTiO₃ thin films by e-beam evaporation were suitable candidates for MLCC application.