CONTROL OF CEO2 GROWTH BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION WITH A SPECIAL SOURCE EVAPORATOR

Epitaxial CeO2 thin films have been grown on (100) yttria-stabilized zirconia (YSZ) and (1 (1) over bar 02) sapphire substrates by metalorganic chemical vapor deposition using a new evaporation apparatus for source delivery. A parametric Study of the evaporator was performed. The substrate temperature effects on crystallinity, in-plane orientation and surface morphology were investigated. The X-ray diffraction data shows the CeO2 films are (100) oriented grown on YSZ substrates when T-s ranges from 650-750 degrees C. However on r-plane sapphire substrates, both the (100) and (111) oriented CeO2 growth are present as evidenced by X-ray diffraction. The peak intensity ratio of (111)/(100) decreased from 75% to 15% when the substrate temperature was increased from 650 degrees C to 700 degrees C. With the use of the new evaporation apparatus, a high deposition rate of 440 Angstrom/min was achieved with a deposition efficiency of 46%. The YBa2Cu3O7-x films grown on CeO2/YSZ and bare-YSZ substrate were compared to demonstrate that the CeO2 films grown by the new MOCVD process are a good buffer for YBa2Cu3O7-x film deposition on YSZ substrates.