Thin (similar to 5.0 nm) Y2O3 films were deposited on n-type Si (1 0 0) substrate using RF magnetron sputtering. Detailed studies on the effects of post-deposition annealing (PDA) temperatures (400, 600, 800, and 1000 degrees C) in argon ambient on these films were performed by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), field emission scanning electron microscopy, and atomic force microscopy. Interfacial layer (IL) of SiO2 in between Y2O3 and the Si substrate for sample annealed from 400 to 800 degrees C had been suggested from the results of FTIR As for sample annealed at 1000 degrees C, presence of IL might consist of both Y2Si2O7 and/or SiO2 through the detection of Y2Si2O7 compound and Si-O chemical bonding from XRD and FTIR analysis, respectively. For as-deposited sample, no detectable chemical functional group at the IL was recorded. Electrical characteristics of the Y2O3 films were acquired by fabricating metal-oxide-semiconductor capacitor as test structure. An improvement in the breakdown voltage (V-B) and leakage current density U) was perceived as the PDA temperature increased. Of the PDA samples, the attainment of the lowest effective oxide charge, interface trap density, total interface trap density, and the highest barrier height at 1000 degrees C had contributed to the acquisition of the highest VB and lowest J. (C) 2011 Elsevier B.V. All rights reserved.