Interfacial and microstructural properties of zirconium oxide thin films prepared directly on silicon

Zirconium oxide thin films were deposited directly on Si by ultra high vacuum electron beam evaporation (UHV-EBE) and rapid thermal annealed (RTA) in O2 ambient at different temperatures ranging from 300 to 800 deg. C. X-ray photoelectron spectroscopy (XPS) revealed zirconium is in the fully oxidized state of Zr4+. X-ray diffraction (XRD) results showed that as-deposited thin films were amorphous. When the annealing temperature increased higher than 700 deg. C, the films began to crystallize. The surface topology was studied with atomic force microscopy (AFM) and the surface of the 700 deg. C-annealed sample was more rougher than that of the 600 deg. C-annealed sample, due to its potentially faceted interfaces. And the typical RMS roughness ranged from 0.546 to 0.666 nm across an area of 50 μmx50 μm. Sharp interfaces between ZrO2 and Si were obtained both by spreading resistance profile (SRP) and cross-sectional transmission electron microscope (XTEM). The interfacial oxide (∼1 nm) was not detected until annealing temperature amounting to 700 deg. C and the exact compositions were not known yet