Improving the electrical properties of niobium-doped titania sputtering targets by sintering in oxygen-deficient atmospheres

Niobium-doped titania (TNO) film can be used as a transparent conductive oxide (TCO) film due to its excellent conductivity and visible transparency. The performances of TNO sputtering targets are thus critical issues in optimizing sputtered films. This study clarifies the influences of inert and reducing atmospheres on the microstructure, densification, crystal structure, and electrical properties of TNO sputtering targets. The results indicate that a sintering atmosphere of 90% Ar-10% H2 can result in a lower sintered density, larger grain size, and lower resistivity than can an atmosphere of Ar, followed by one of air. Sintering in 90% Ar-10% H2 or Ar obviously decreases the resistivity of TiO2, from >108 Ω cm to <10−1 Ω cm, and the TNO target, from >101 Ω cm to <10−1 Ω cm. The resistivity of TNO target sintered at 1200 °C in 90% Ar-10% H2 is as low as 1.8×10−2 Ω cm.