Atomic and electronic structures of amorphous ZrO2 and HfO2 films

Atomic and electronic structures of ZrO2 and HfO2 films deposited using sputtering technique were studied by X-ray diffraction (XRD), EXAFS spectroscopy, photoemission (with X-ray and ultraviolet excitation sources) and electron energy loss spectroscopy (EELS). XRD results indicated that the as-deposited films were amorphous and a monoclinic phase was detected after annealing them in ambient at 800 degrees C. Photoemission results indicated that the ZrO2 valence band consists of two bands separated by an ionic gap of 6 eV. The lower band of 10 eV width is occupied mainly by 0 2s states. EELS results indicated that the bandgap of ZrO2 and HfO2 films are 4.7 and 5.7 eV, respectively. (c) 2005 Published by Elsevier B.V