In this study, Y₂O₃ thin films were deposited on Si(100) wafers using an RF sputtering system with a Y₂O₃ target. The Y₂O₃ thin film was confirmed to have a thickness of 227 nm/min and a uniformity of 1.34% at a substrate temperature of 400℃. All samples were annealed at 600, 800, and 1,000℃ for 1 hour in an O₂ gas atmosphere using the furnace. The analysis of the XRD patterns revealed that the peak intensity increased with annealing up to 800℃, but decreased when the annealing temperature was raised to 1,000℃. The XPS analysis confirmed the onset of crystallization at 800℃, in agreement with the trends observed in the XRD results. According to the AFM results, the surface became slightly smoother after heat treatment, as indicated by a reduced RMS roughness of approximately 1.792 nm.

We investigated a solution-derived Y₂O₃ film treated by ion beam (IB) irradiation as a liquid crystal (LC) alignment layer. With IB irradiation, homogeneous LC alignment was achieved irrespective of the annealing temperature. To verify the effect of IB irradiation, we conducted surface analyses such as X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). As Y₂O₃ is a high-k material, the electro-optical properties of the twisted nematic (TN) cells were superior to those of conventional TN cells based on a rubbed polymer, with an LC rising time of 4.1ms and falling time of 2.9ms. The IB-irradiated Y₂O₃ is a good alternative as an alignment layer for fast-switching TN LC displays.