GROWTH, STRUCTURAL CHARACTERIZATION AND INTERFACIAL REACTION OF MAGNETRON SPUTTERED CeO2 THIN FILMS ON DIFFERENT SUBSTRATES

CeO2 thin films were deposited on Si, Al, Ti–6Al–4V alloy, Si3N4 and glass substrates by magnetron sputtering at room temperature. Growth of CeO2 films on Si and Si3N4 and effect of annealing were investigated by XRD, FESEM and AFM. Interaction between deposited CeO2 films and Si, Al, Ti–6Al–4V alloy, Si3N4 and glass substrates was investigated by XPS. XRD studies show that films are oriented preferentially to (200)-direction of CeO2 and no significant change is observed in the XRD patterns of films after heat treatment. CeO2 film on Si3N4 exhibits rough morphology, whereas very fine morphology is observed in CeO2 film on Si. CeO2 film on Si shows lower roughness in relation to that on Si3N4 as demonstrated by AFM studies. XPS results show that Ce is present as both +4 and +3 oxidation states in CeO2 film deposited on Si and Al substrates, whereas Ce4+ is the main species in CeO2 films deposited on Ti–6Al–4V alloy, Si3N4 and glass substrates. Ce3d, Si2p and O1s core level spectra demonstrate that Ce2O3 or cerium silicate and SiOx type of species are formed at the interface of CeO2 and Si. Similarly, formation of interfacial species like Ce2O3 or cerium aluminate is evident in CeO2 film on Al as demonstrated by XPS studies. On the other hand, interfacial reactions between CeO2 and Ti–6Al–4V alloy, Si3N4 and glass substrates are limited in the respective films.