ZrO2 films are deposited on bare silicon, silicon with a pre-sputtered ultrathin Zr metal layer, and plasma oxynitrided Si surface by reactive sputtering and the growth of interface layer between ZrO2 and Si is investigated. The ZrO2/Si dielectric stacks, before and after annealing in oxygen ambient, are characterized by grazing incident angle X-ray diffraction, Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy, transmission electron microscopy, capacitance-voltage and current-voltage measurements. The results reveal that as-deposited ZrO2 films contain nanocrystallites embedded in the amorphous matrix. ZrO2 films deposited on an ultrathin Zr metal layer show a thinner interface layer but contain a greater amount of oxide traps. ZrO2 films deposited on SiOxNy grown by NH3 plasma oxynitridation are found to retard the growth of the interface layer effectively, and they also exhibit fewer oxide traps and lower leakage currents. (c) 2006 Elsevier B.V. All rights reserved.