Abstract
Tin-doped indium oxide (ITO) films have been deposited by RF sputtering an oxide target onto substrates held at different distances from the target surface. The deposition rate is constant up to a target-to-substrate distance of 3.5 cm and decreases with further increase in substrate distance, this distance being associated with the thermalisation (virtual source) distance of the sputtered neutrals. The properties of the films are observed to be dependent on the target-to-substrate distance. Films deposited onto a substrate held 2 cm from the target have preferred orientation (440), lattice constant a=10.21+or-0.02 AA and band gap 3.5 eV; films deposited onto a substrate held 8 cm from the target have preferred orientation (222), lattice constant a=10.29+or-0.02 AA and band gap 3.7 eV. The observed differences in the properties are attributed to the different energies of the sputtered neutrals reaching the substrates.