Effect of Electron Incidence in Epitaxial Growth of CeO2(110) Layers on Si(100) Substrates

Abstract

ABSTRACTWith the aim of lowering epitaxial growth temperature, the effect of electron incidence is studied in the epitaxial growth of CeO2(110) layers on Si(100) substrates by electron-beam evaporation in an ultrahigh vacuum. Two growth methods are employed: evaporation under substrate bias application and electron-beam assisted evaporation. In evaporation at positive substrate bias, electrons and anions from an evaporation source are attracted to the substrate surface, resulting in successful epitaxial temperature lowering. It is clarified that facilitation of the epitaxial growth is attributed only to electron incidence. The electronic current component is measured to be on the order of 10−4 A, about half of the total current. In using electron-beam assisted evaporation for higher current (10−3 A), electron-beam irradiation is demonstrated to have a much greater effect in both the growth temperature lowering and the crystalline quality improvement. The epitaxial growth facilitation effect increases with electron energy in both evaporation methods. It is clarified that the epitaxial growth temperature is lowered to 720°C, i. e., epitaxial growth temperature lowering of ∼100°C compared with the conventional growth method, both by evaporation with substrate bias at +240 V and 240 eV-electron-beam assisted evaporation, wherein the latter produces higher crystalline quality layers.