Influence of Substrate Orientation and Oxygen Partial Pressure on the Morphology, Structure, and Electrical Property of Epitaxial Indium Tin Oxide Films

Indium tin oxide (ITO, tin-doped indium oxide) has been widely used in optoelectronic and other research fields because of its excellent electrical conductivity. However, there is a lack of systemic research on the influence of crystal orientation on the electrical properties of epitaxial ITO films. In this work, the epitaxial ITO films were deposited on low index planes of yttria-stabilized zirconia substrates by direct current magnetron sputtering at different oxygen partial pressures ranging from 0 to 3 Pa. The carrier concentration of the ITO film decreased with the increase of the oxygen partial pressure and further leading to the increase of overall resistivity. In addition, we also found that the Hall mobilities of ITO (100) films rapidly decreased with the oxygen partial pressure, while the Hall mobilities of ITO (111) films remained unchanged. The anisotropy of the carrier mobility was the main factor for the resistivity difference of ITO films with different orientations at high oxygen partial pressure.