Yttria-stabilized zirconia (YSZ) heteroepitaxially grown on Si substrates by reactive sputtering

Yttria-stabilized zirconia (YSZ) thin films were grown on Si(1 0 0), (1 1 0) and (1 1 1) substrates by reactive magnetron sputtering. The deposition was performed in metallic mode using a Zr metal target arranged with Y plates and an aperture for the prevention of target oxidation. Reflection high-energy electron diffraction (RHEED) and X-ray diffraction (XRD) analysis, showed YSZ to be epitaxially grown on Si(1 0 0) at a substrate temperature of 800 degreesC, indicated by sharp streaks in the RHEED pattern. On the other hand, YSZ films deposited on Si(1 1 0) deposited at 600-800 degreesC were all polycrystalline. Although, YSZ on Si(1 1 1) showed a strong orientational dependence on the substrate, its crystallinity seemed to be degraded by the generation of twin structures. This preferential growth orientation of YSZ was discussed considering the arrangement of YSZ unit cells on Si substrates with various lattice orientations. The YSZ/Si interfaces, which showed epitaxial growth, were observed by the cross-sectional transmission electron microscope (XTEM), and YSZ crystal growth mechanisms were speculated on the basis of their electrical characteristics. (C) 2000 Elsevier Science Ltd. All rights reserved.