Electrical and optical properties of indium tin oxide thin films deposited on unheated substrates by d.c. reactive sputtering

Abstract

Transparent conducting thin films of indium tin oxide (ITO) have been deposited by d.c. reactive planar magnetron sputtering by using metal InSn alloy target in an ArO 2 gas mixture. The study demonstrates that the deposition on unheated substrates achieved sheet resistance of as low as about 50–60 Ω/□ (or a resistivity of abouts 7 × 10 −4 Ω cm), and visible transmission of about 90% for a wavelength of 420 nm. The effects of heat treatment at 450 °C in air depends on the deposition conditions of the as-deposited ITO films. Although annealing improves the properties of as-deposited ITO films which were deposited with non-optimum conditions, the optimized condition for the formation of the film in the as-deposited state is essential to obtain a high quality transparent conducting coating.