Structure and Internal Stress of Tin-Doped Indium Oxide and Indium–Zinc Oxide Films Deposited by DC Magnetron Sputtering

Abstract

Representative transparent conductive oxide films, such as tin-doped indium oxide (ITO) and indium–zinc oxide (IZO) films, were deposited by dc magnetron sputtering using corresponding oxide targets under various total gas pressures (Ptot) ranging from 0.3 to 3.0 Pa. The ITO films deposited at a Ptot lower than 0.7 Pa were polycrystalline and were found to have a large compressive stress of about 1.5 ×109 Pa, whereas the ITO films deposited at 1.5–3.0 Pa were amorphous and had a low tensile stress. In contrast, all the IZO films deposited at a Ptot range of 0.3–3.0 Pa showed an entirely amorphous structure, where the compressive stress in the IZO films deposited at a Ptot lower than 1.5 Pa was lower than that in the ITO films. Such compressive stress was considered to be generated by the atomic peening effect of high-energy neutrals (Ar0) recoiled from the target or high-energy negative ions (O-) accelerated in the cathode sheath toward the film surface.