Low-resistivity sputtered films of transparent conducting Ta-doped in ₂O ₃ oxide

Low-resistivity Ta-doped Ir ₂O ₃ (InTaO) films were grown on Corning # 1737 glass substrates from a ceramic target of (In _0.95Ta _0.05) ₂O ₃ by radio-frequency magnetron sputtering. The electrical and the optical properties of these films were investigated by varying the oxygen partial pressure pO ₂ (0 Torr ≤ pO ₂ ≤ 1.0 × 10 ^-4 Torr) and the deposition temperature T _S (25°C ≤ T _S ≤ 350° C) during the deposition. The film grown at 350°C and pO ₂ = 0 Torr showed a resistivity as low as 0.28 mΩcm with a carrier density of 7.4 × 10 ²⁰ cm ^-3, a Hall mobility of 30.1 cm ²V ^-1s ^-1, an optical band gap of 4.04 eV, and an average transmittance above 85 % for wavelengths between 400 and 700 nm. These values are comparable to those of optimized Sn-doped In ₂O ₃ (ITO).