Optical Properties of RF-Sputtered Indium Oxide Films

In2O3 films are prepared by rf-sputtering from an oxide target onto quartz substrates in an argonoxygen atmosphere. The oxygen partial pressure is varied in the range from 2 × 10−4 Pa to 3 × 10−3 Pa. The optical constants of these films are determined from the measured transmittance and reflectance in the region from 2.5 to 0.35 μm. The analysis shows that the films are optical inhomogeneous with an index of refraction at the interface In2O3—quartz and the energy gap Eg similiar to those for bulk material, whereas the refraction coefficient at the upper surface of the films depends on the oxygen partial pressure of the sputter gas in a similiar manner as it is stated for the electrical properties.