Indium oxide-based transparent conductive films deposited by reactive sputtering using alloy targets

Abstract

High-quality transparent conductive oxide (TCO) films, Sn-doped In2O3 (ITO) and In2O3–ZnO (IZO), were successfully deposited on either synthetic silica or polyethylene terephthalate (PET) substrates in the “transition region” by reactive dc magnetron sputtering using In–Zn and In–Sn alloy targets, respectively, with a specially designed plasma emission feedback system. The composition, crystallinity, surface morphology, and electrical and optical properties of the films were analyzed. All of the IZO films were amorphous, whereas the ITO films were polycrystalline over a wide range of deposition conditions. The minimum resistivities of the IZO and ITO films deposited on the heated PET substrates at 150 °C were 3.3 × 10−4 and 5.4 × 10−4 Ω·cm, respectively. By applying rf bias to unheated PET substrates, ITO films with a resistivity of 4.4 × 10−4 Ω·cm were deposited at a dc self-bias voltage of −60 V.