What is ITO Sputter Deposition

ITO, or tin-doped indium-oxide, coatings used on optically clear polymer films are specially designed to reduce glare and enhance clarity in digital displays. The ITO coatings provide excellent electrical conductivity and optical transparency and are therefore used as transparent electrodes in most display products.

Indium Oxide/Tin Oxide is among one of the most heavily utilized compounds in the thin film industry due to its electrical conductivity and optical transparency. ITO belongs to a family of evaporative materials known as transparent conductive oxides.

These unique coatings can be deposited by reactive electron-beam evaporation onto varying flexible substrates. ITO is the industry standard for transparent conductive films as it is robust, has good sheet resistance range, and high UV-Visible and Near IR transmission.

Because ITO is a transparent material, it can be stacked onto a film with other dielectric materials to create a conductive anti-reflective coating. Such coatings can be deposited either in a purely reactive sputter process from metallic In-Sn alloy targets or from ceramic ITO targets using a quasi-reactive process.

The latter technology implemented as DC magnetron sputtering prevails today in the display technology industry. The formation of nodules on the target surface during the sputtering process over time is associated with the fact that indium-oxide exists in three allotropic phases. Such nodules are a source of process instability and of coating pinholes. The usage of rotary cathodes is a way to eliminate or at least strongly reduce this problem. Such cathodes also give rise to considerably reduced coating costs, as will be illustrated with applications taken from the LCD and touch panel industries.