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.

Properties of ITO films deposited by RF superimposed DC magnetron sputtering

“…However, the peak intensity decreased with further increases in RF/(RF + DC). This might be due to the damage caused by high energy particles and the degradation of crystallinity, which is affected by the excessively high energy of Ar + accelerated by V p -V f at the substrate [12]. This result shows a good correlation with the electrical properties, as shown in Fig.…”

“…In the case of power ratio of RF/ (RF + DC) > 71.4%, the resistivity increased with increasing RF portion of the total power. This behavior may be due to the adverse effects of the excessively high energy of Ar + accelerated by V p -V f near the growing film surface [12]. The ITO films deposited near the crystallization temperature (170°C) had a lower resistivity than the ITO films deposited at RT.…”

“…In RF magnetron sputtering, the electron temperature is higher than that in DC magnetron sputtering, resulting in a higher V p -V f , where V p and V f are the plasma and floating potentials, respectively. In addition, ITO films deposited by DC magnetron sputtering are damaged more by the atomic peening effect of the high energy negative ions (O À ) and high energy neutrals (Ar 0 ) compared with the ITO films deposited by RF magnetron sputtering [12][13][14]. Therefore, the ITO films deposited by RF superimposed DC magnetron sputtering have properties intermediate between those deposited by RF and DC magnetron sputtering only, which leads to the optimum resistivity.…”

Improving the delamination resistance of indium tin oxide (ITO) coatings on polymeric substrates by O2 plasma surface treatment

“…However, the degree of changes in size and density is similar in ITO with the same h ITO and seems not affected by the surface treatment. This result indicates that ITO with the same h ITO may have the similar cohesive strength [16] regardless of the surface treatment.…”

Crystallization behavior during transparent In2O3‐ZnO film growth

“…Amorphous IZO films are suitable for flexible substrates as there are few internal stresses or severe cracking generated between the film and flexible substrate [1][2][3][4]. The stability of IZO films with respect to their level of crystallization and respective change in resistivity is particularly important for future technological applications.…”