Takeshi Hattori

Sn- or Hf-doped InSbO4 films deposited by RF magnetron sputtering

Abstract Indium antimonate (InSbO4) films were deposited on surface oxidized Si wafer (SiO2/Si) or fused silica glass substrates at 400 °C by RF magnetron sputtering. The sputtering depositions were carried out with the mixture gas of Ar (40%) and O2 (60%) using a sintered ceramic disk of In0.4Sb0.6O2.1 as target whose compositions were the optimized values to deposit stoichiometric InSbO4 films with the highest crystallinity. In order to investigate the possibility of enhancing carrier density by the impurity dopings, Sn, Hf, Mo and W were tried to be doped into the InSbO4 films. Sn and Hf were confirmed to be effective as dopants for the InSbO4 to increase carrier density, whereas W and Mo were ineffective. The InSbO4 film doped by 7 at.% Sn showed a minimum resistivity of 9.7×10−3 Ωxa0cm, where carrier density and mobility were 2.5×1020 cm−3 and 2.6 cm2xa0V−1xa0s−1, respectively. The optical band gaps of the non-doped and 7 at.% Sn-doped films were estimated to be approximately 4.05 and 4.2 eV, respectively. The 7 at.% Sn-doped InSbO4 film showed minimum resistivity of 3.3×10−3 Ωxa0cm after post-annealing at 400 °C in air for 1 h, where carrier density and mobility were 4.1×1020 cm−3 and 5.4 cm2xa0V−1xa0s−1, respectively.