Evolution of the microstructure of oxide thin films

The film growth of CeO2 by metal-organic chemical vapor deposition (MOCVD) was studied. Samples of different thicknesses (d = 10-500 nm) on SrTiO3 as well as on yttria stabilized zirconia were prepared and analysed by X-ray diffraction (theta/2 theta-scan, omega-scan), scanning electron microscopy (SEM), and Rutherford backscattering spectroscopy (RES). The films grew with a preferential orientation and a CeO2[001]//substrate[001] was found. The rocking: curves in the omega-scans exhibited a two-component shape in very thin films. A crossover depending on the substrate material was observed at higher film thicknesses leading to a one-component curve. The complex behavior in the film evolution of the CeO2 system will be discussed, and a model of the film growth mechanism will be proposed.