Growth, characterization and interfacial reaction of magnetron sputtered Pt/CeO2 thin films on Si and Si3N4 substrates

摘要

Pt/CeO2 thin films were deposited on Si and Si3N4 substrates by magnetron sputtering at room temperature. Growth of the films on Si and Si3N4 were characterized by XRD, FESEM and AFM. Interaction of Pt/CeO2 films with Si in Si and Si3N4 substrates was extensively investigated by XPS. XRD studies show that films are oriented preferentially to (200) direction of CeO2. XPS results show that Pt is mainly present in +2 oxidation state in Pt/CeO2/Si film, whereas Pt4+ predominates in Pt/CeO2/Si3N4 film. Ce is present as both +4 and +3 oxidation states in Pt/CeO2 films deposited on both Si and Si3N4 substrates, but concentration of Ce3+ species is observed to be more in Pt/CeO2/Si film. Interfacial reaction between CeO2 and Siudsubstrate is controlled in presence of Pt. Pt/Ce concentration ratio decreases in Pt/CeO2/Si3N4 film upon successive sputtering, whereas this ratio decreases initially and then increases in Pt/CeO2/Si film. Pt is segregated at the interface in Pt/CeO2/Si film, whereas Pt is diffused outwards in Pt/CeO2/Si3N4 film as observed from depth profiling studies.