Surface and mechanical characterization of ITO coatings prepared by microwave-assisted magnetron sputtering process

In this paper, indium-tin oxide (ITO) thin films were deposited on various substrates, such as microscope slides, silica and silicon, using microwave-assisted reactive magnetron sputtering process. Deposited coatings were amorphous according to the X-ray diffraction results. Atomic force microscopy investigations revealed that the surface of thin films is homogenous and very smooth. Prepared ITO thin films exhibit high transparency in the visible light range and the transmittance factor is above 80%. Besides very good optical properties, deposited thin films also exhibits low surface resistance, which was measured with the aid of a four-point probe. To evaluate the properties of prepared thin films as transparent conducting oxide coatings, the figure of merit was calculated. Mechanical properties of deposited thin films were evaluated based on nanoindentation method. The hardness of ITO coatings was high and equal to ca. 16GPa. To complete the investigation of the tribological properties of prepared thin films, the scratch steel wool test was performed and showed that only few scratches were observed. It did not affect the transparency of the thin film, and scratches were hardly visible with the aid of an optical microscope. However, measurements performed with the use of optical profilometer have shown that the depth of scratches was from ca. 300 to ca. 320 nm, what indicates that in place of scratches, thin film was completely removed from the substrate. Copyright (C) 2014 John Wiley & Sons, Ltd.