Sputtered barium titanate and barium strontium titanate films for capacitor applications

Thin barium titanate and barium strontium titanate films are being developed as dielectric film for use in dc-dc converters. Thin BaTiO₃ (BT) and (BaSr)TiO₃ (BST) film capacitor devices were fabricated using RF magnetron sputtering techniques. The typical dielectric constant of these film capacitors was in the range of 300 to 690. These film capacitors had dissipation factors between 0.2% to 0.6% before annealing. The film capacitors have breakdown voltages in the range of 1×10⁵ to 1.2×10⁶ V/cm. The resistivity was in the range of 10¹³ to 10¹⁴ ohm-cm. Annealing significantly increased the value of the dielectric constant. Annealing also increased the value of the dissipation factors up to 2%. The capacitance of these films had little dependence on frequency from 400 Hz to 100 kHz. Thermal cycling in the temperature range of 50 to 300°C had very limited impact on the capacitance and dissipation factor. Measurements of dielectric and material properties are reported