High quality indium tin oxide (ITO) film growth by controlling pressure in RF magnetron sputtering

This paper presents the significant role deposition pressure plays in the deposition of high quality ITO films by RF magnetron sputtering. ITO target was sputtered onto bare sodalime glass under various deposition conditions. Particularly, the deposition pressure was varied against several other parameters, until the best film characteristics were obtained. The deposited films were characterized using FESEM, AFM, XRD, UV-Vis and four-point probe. Results indicate that deposition pressure plays significant role in obtaining good quality films. ITO grains change dramatically with pressure, having lower pressure giving better morphology. In addition, lower pressure also produced films with lower resistivity but lower transmittance and poor crystallinity. By separately and collectively optimizing the deposition conditions, ITO films of 160-200nm thickness, having resistivity of 7.56×10^-5 Ω-cm with 87% transmittance were obtained. To our knowledge, this is the lowest resistivity ITO films produced by magnetron sputtering. This work confirms that even though deposition temperature and RF power have overbearing influence on the film properties, but the deposition pressure also contributes significantly in obtaining good quality films.