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

Abstract Indium antimonate (InSbO 4 ) films were deposited on surface oxidized Si wafer (SiO 2 /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 O 2 (60%) using a sintered ceramic disk of In 0.4 Sb 0.6 O 2.1 as target whose compositions were the optimized values to deposit stoichiometric InSbO 4 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 InSbO 4 films. Sn and Hf were confirmed to be effective as dopants for the InSbO 4 to increase carrier density, whereas W and Mo were ineffective. The InSbO 4 film doped by 7 at.% Sn showed a minimum resistivity of 9.7×10 −3 Ω cm, where carrier density and mobility were 2.5×10 20 cm −3 and 2.6 cm 2  V −1  s −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 InSbO 4 film showed minimum resistivity of 3.3×10 −3 Ω cm after post-annealing at 400 °C in air for 1 h, where carrier density and mobility were 4.1×10 20 cm −3 and 5.4 cm 2  V −1  s −1 , respectively.