Surface morphology analysis in correlation with crystallinity of CeO2(110) layers on Si(100) substrates

CeO2 layers having various crystallinity are prepared in the vicinity of the critical condition for epitaxial growth, using conventional evaporation and electron beam assisted evaporation. Surface morphology of CeO2 layers is studied using atomic force microscopy in correlation with crystallinity of the layer determined by reflection high energy electron diffraction. It is clearly observed that surface morphology changes with crystallinity of the CeO2 layers. Single crystal CeO2(110) layers have a nanometer-scale-periodically corrugated surface structure, which consists of (111) facets. As the crystalline quality of samples becomes worse, the number of irregular shaped hillocks and tetrahedral hillocks increases, which correspond to distorted (110) grains and (111)-oriented polycrystalline grains, respectively. It is found that crystalline quality is not uniform but various crystallinity regions are distributed from place to place and their population ratio changes according to the degree of crystalline quality. The surface of polycrystalline layers with a tendency of (111) orientation consists of tetrahedral hillocks with irregular in-plane rotational orientations within the horizontal plane. These features are discussed in terms of the surface propel dcs of the substrates at the early stage of growth. [S0734-2101(00)13804-7].