Metal–insulator–metal capacitors using Ba2Ti9O20 dielectric thin film

The dielectric properties of Ba2Ti9O20 film were investigated to evaluate its potential use in metal–insulator–metal (MIM) capacitors. A homogeneous crystalline Ba2Ti9O20 phase without any second phase developed for the film grown at 700 °C and rapid thermal annealed at 900 °C for 3 min. The 200 nm-thick Ba2Ti9O20 film showed a capacitance density of 2.0 fF/μm2 with a low dissipation factor of 0.016 at 100 kHz. The capacitance density of the film was low, but it could be increased by decreasing the thickness of the film. The leakage current density was approximately 0.094 nA/cm2 at 1 V. A small linear voltage coefficient of capacitance of −690 ppm/V was obtained, together with a quadratic one of −67.41 ppm/V2 and a small temperature coefficient of capacitance of −168.87 ppm/°C at 100 kHz. All these results show that the Ba2Ti9O20 film is a good candidate material for MIM capacitors.