EPITAXIAL-GROWTH OF MONOCLINIC AND CUBIC ZRO2 ON SI(100) WITHOUT PRIOR REMOVAL OF THE NATIVE SIO2

High-quality epitaxial thin films of pure and yttria-stabilized ZrO2 (YSZ) were deposited onto Si(100) by electron beam evaporation at substrate temperatures around 880-degrees-C. No specific wafer cleaning was employed to remove the native SiO2. X-ray diffraction revealed a monoclinic structure for the pure ZrO2 whereas a cubic structure was observed for the YSZ. X-ray pole figure analysis showed that in both cases the in-plane axes of the films were essentially parallel to the Si[010] and [001] directions. Rutherford backscattering and channelling analysis resulted in minimum yield values of 7% and 6% for the pure ZrO2 and the YSZ films respectively, thus indicating a high degree of crystalline perfection. A 20 angstrom thick amorphous SiO2 layer was observed at the interface using high resolution transmission electron microscopy. It was probably regrown during film deposition, after the original surface oxide of the wafer has been removed in situ.