Donor generation from native defects induced by In+ implantation into tin-doped indium oxide

Low-resistivity tin-doped indium oxide thin films have been implanted with 115In+ ions in order to increase the concentration of electrically active oxygen vacancies. The carrier density, Hall mobility, and optical properties of the as-implanted films have been determined as a function of In+ dose. Three dose ranges are described. For doses up to 2.5×1014/cm, both carrier density and Hall mobility initially decrease to respective saturation values. Then, at doses between 2.5×1014/cm2 and 2.5×1015/cm2, the carrier density increases while the mobility remains constant. At still higher doses, the Hall mobility begins to decrease abruptly. Mechanisms accounting for the implantation-induced changes in each of these three dose ranges are discussed. In particular, it is shown that the rate of increase of the carrier density with In+ dose in the intermediate range agrees quantitatively with the rate of production of oxygen-vacancy donors that is necessary to fully accommodate the implanted In substitutionally on In2O3 lattice sites during implantation.