Hafnium oxide (HfO2) thin films have been made by radio-frequency (rf) magnetron-sputtering onto Si(1 0 0) substrates under varying growth temperature (T-s). HfO2 ceramic target has been employed for sputtering while varying the T-s from room temperature to 500 degrees C during deposition. The effect of T-s on the growth and microstructure of deposited HfO2 films has been studied using grazing incidence X-ray diffraction (GIXRD), and high-resolution scanning electron microscopy (HR-SEM) coupled with energy dispersive X-ray spectrometry (EDS). The results indicate that the effect of T-s is significant on the growth, surface and interface structure, morphology and chemical composition of the HfO2 films. Structural characterization indicates that the HfO2 films grown at T-s < 200 degrees C are amorphous while films grown at T-s > 200 degrees C are nanocrystalline. An amorphous-to-crystalline transition occurs at T-s = 200 degrees C. Nanocrystalline HfO2 films crystallized in a monoclinic structure with a (-1 1 1) orientation. An interface layer (IL) formation occurs due to reaction at the HfO2-Si interface for HfO2 films deposited at T-s > 200 degrees C. The thickness of IL increases with increasing T-s. EDS at the HfO2-Si cross-section indicate that the IL is a (Hf, Si)-O compound. The electrical characterization using capacitance-voltage measurements indicate that the dielectric constant decreases from 25 to 16 with increasing T-s. The current-voltage characteristics indicate that the leakage current increases significantly with increasing T-s due to increased ILs. (C) 2010 Elsevier B.V. All rights reserved.