Microstructure and Electrical Properties of Amorphous Bi 5 Nb 3 O 15 Films Grown on Cu/Ti/SiO 2 /Si Substrates Using RF Magnetron Sputtering

Amorphous Bi5Nb3O15 (BNO) films were grown at room temperature (RT) on a Cu/Ti/SiO2/Si substrate using radio frequency magnetron sputtering. All the films were well formed on the Cu electrode with a sharp interface between the film and the electrode. The dielectric constant of the amorphous BNO film grown under 25 W was 46, with a low dissipation factor of 2.7% at 100 kHz. This film exhibited a low leakage current density of 5.5 × 10 −8 A/cm 2 at 4.5 V and a large breakdown voltage of 7.2 V. However, the electrical properties deteriorated as the sput- tering power and the growth temperature increased due to the increased surface roughness; this was because a film with a rough surface generally has a larger surface area, and there can be electric field intensification at surface asperity, which degrade the electrical properties of the film. In addition, the electrical properties were not influenced by the oxygen partial pressure (OPP) because the variation of OPP during the growth of the films did not affect their surface roughness. The amorphous BNO film grown on the Cu/Ti/SiO2/Si substrate at RT under 25 W may be a good candidate material for an embedded capacitor. Index Terms—Bi5Nb3O15 thin films, Cu electrode, high di- electric constant, metal-insulator-metal (MIM) capacitor, surface roughness.