A study of the interface of CeO 2⧹Si heterostructure grown by ion beam deposition

Abstract

Epitaxial cerium dioxide films on single-crystal silicon substrates (CeO 2⧹Si) have been grown by a dual mass-analyzed low-energy ion beam deposition (IBD) system. By double-crystal X-ray diffraction (XRD), Full Width at Half Maximum (FWHM) are 23″ and 33″ in the rocking curves for (222) and (111) faces of the CeO 2 film, respectively, and the lattice-mismatch Δ a⧹a with the substrate is about −0.123%. The results show that the CeO 2⧹Si grown by IBD is of high crystalline quality. In this work, the CeO 2⧹Si heterostructure were investigated by X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) measurements. Especially, XPS and AES depth profiling was used to analyze the compositions and structures in the interface regions of the as-grown and post-annealed CeO 2⧹Si. It was found that there was no silicon oxide in the interface region of the as-grown sample but silicon oxide in the post-annealed sample. The reason for obtaining such high quality heterostructure mainly depends on the absence of silicon oxide in the surface at the beginning of the deposition.