Non-epitaxial growth and electrical properties of highly (222)-oriented ITO thin films

Abstract

The crystallographic orientation of transparent conducting oxides is a critical determinant of their functional properties. Herein, we demonstrate the non-epitaxial growth of highly (222)-oriented indium tin oxide (ITO) films on quartz substrates via magnetron sputtering, mediated by a yttria-stabilized zirconia (YSZ) buffer layer. The YSZ layer not only provides a stable template for preferential ITO growth but also ensures exceptional process robustness. Morphological analysis reveals a quasi-triangular grain morphology and a continuous vertical columnar growth mode throughout the film thickness. Following optimization of an in situ annealing process, the ITO films exhibit a low resistivity of 1.65 × 10−4 Ω cm and a high figure of merit of 0.039 Ω−1. This overall performance surpasses that of commercial ITO benchmarks and most values reported in the literature.