Epitaxial growth of CeO2 was obtained on the Si(111) surface by laser ablation in UHV atmosphere. However, a dual amorphous layer formed at the interface, yielding a CeO2/α:-CeOx/α-SiO2/Si(111) structure. This structure is speculated to be caused by a reaction occurring between Ce oxide and Si. Post annealing in O2 ambient caused the regrowth of CeO2, eliminated the α-CeOx layer, and increased the thickness of the SiO2 layer. The new CeO2/SiO2/Si(111) structure shows improved breakdown voltage and fewer interfacial states as observed by C-V and I-V measurements. The SiO2 is expected to tie surface states with Si, whereas the single crystal CeO2 will allow the epitaxial growth of lattice-matched Si on this insulating film. The effect of growth conditions and O2 annealing on both the structural and the electrical properties of this epitaxial oxide will be presented.