Fabrication of Structurally Simple Index-Matched ITO Films Using Roll-to-Roll Sputtering for Touch Screen Panel Devices

We report the electrical and optical properties of structurally simple refractive-index-matched indium tin oxide (IM-ITO) films prepared on high-refractive index hard-coated polyethylene terephthalate (KM-V2) substrates by using a pilot scale roll to roll magnetron sputtering system for implementation in touch screen panels. We found that the ITO thin films are polycrystalline with a preferred (222) orientation. We determined the appropriate conditions for the deposition of simple-structure IM-ITO films on KM-V2 substrates for touch screen panels with an invisible electrode pattern. Moreover, the outgassing of the polymer substrate is very important in the roll-to-roll sputtering fabrication of high-quality IM-ITO films with the required electrical and optical properties.