Electrical properties of amorphous BaTi₄ O₉ films grown on Cu / Ti / SiO₂/ Si substrates using RF magnetron sputtering

Amorphous BaTi₄O₉ (BT4) films for use as capacitors embedded in PCB substrates were grown on Cu electrodes at low temperatures (≤ 200°C). The dielectric constant (k) of the amorphous BT4 film grown at room temperature (RT) was 38, and its dissipation factor was 3.2% at 100 kHz. A similar k value was obtained at radio-frequency ranges, with a quality factor of 143 at 1.0 GHz. The films showed a capacitance density of 200 nF/cm ², a temperature coefficient of capacitance of 296 ppm/°C at 75 kHz, and a breakdown voltage of 42.5 V. This film therefore satisfies the requirements of the International Technology Roadmap for Semiconductors for 2016 for capacitors grown on organic substrates. In addition, the leakage current mechanism of the amorphous BT4 films was found to be Schottky emission, and the Schottky barrier height was calculated as 2.26 eV.