Properties of ITO thin films deposited by RF magnetron sputtering at elevated substrate temperature

Indium tin oxide films have been deposited by RF magnetron sputtering technique. Discharge power density has been varied from 0.36 to 2 W cm−2 and pure argon or argon/oxygen mixture have been utilised as sputtering gas. Substrate temperature has been kept at 250°C for all the samples. Filmʹs crystallisation behaviour has been investigated as a function of RF power density. XRD analysis revealed a change in preferential orientation of polycrystalline crystalline structure from (222) to (400) plane with the increase in RF power. Crystallite size was found to increase with the RF power. EPMA analysis revealed a higher O/In ratio in the 〈111〉 oriented samples than in the 〈100〉 oriented ones. In/Sn ratio, evaluated by ICP analysis, decreased with the increase in RF power and with the change of sputtering gas from pure Ar to Ar/O2 mixture. Optical band gap was found continuously decreasing with the increase in RF power. Hall effect measurement showed the influence of high deposition power on the electron mobility degradation. A very low electrical resistivity of 8.6×10−5 Ω cm−1 was achieved during this investigation. A close correlation between the preferential orientation and film properties has been pointed out.