EFFECTS OF ION ENERGY AND ARRIVAL RATE ON THE COMPOSITION OF ZIRCONIUM-OXIDE FILMS PREPARED BY ION-BEAM-ASSISTED DEPOSITION

Thin zirconium oxide films were grown using the ion-beam assisted depo sition method. Zirconium metal was evaporated by an electron beam and condensed on a Si substrate, while oxygen ions were directed simultane ously onto the substrate, allowing the fundamental deposition paramete rs of ion energy and arrival rate ratio ARR(O/Zr) to be measured and c ontrolled easily. X-ray photoelectron spectroscopy (XPS) was used to s tudy the oxidation and the composition of the films. XPS analyses indi cated the presence of four oxidation states of zirconium (Zr4+ - Zr(1)) in Zr 3d spectra and two peaks in O 1s spectra; Zr4+ is a predomina nt ion in all the films and the two peaks in O 1s spectra are related to the oxide and to hydroxyl groups and/or carbonates, respectively. C omposition analyses of the films suggested that these oxygen-associate d species may be bound to zirconium. The variation of composition as a function of ion energy (from 2 to 20 keV) and ARR(O/Zr) (at 0.54 and 1.09) could be explained with the preferential sputtering of zirconium from the growing film by incoming oxygen ions and the incorporation o f oxygen ions into the film. (C) 1996 American Institute of Physics.