The active dopant concentration in ion implanted indium tin oxide thin films

Abstract

The effect of oxygen ion implantation on the electrical and optical properties of Sn-doped In2O3 (ITO) thin films, sputter deposited from a planar magnetron source on glass substrates, is described. The films were characterized as a function of the implanted dose (3×1013–1×1016 O+ cm−2) by Hall effect, resistivity, and optical transmission measurements. The dependencies observed are explained in terms of the deactivation of the Sn dopant and the removal of oxygen vacancies. In this way an estimate of the amount of electrically active Sn contributing to the carrier density in as-deposited films was obtained. Furthermore, the accompanying changes in the band gap with decreasing free-carrier density could be explained quantitatively in terms of the Burstein–Moss effect.