Physical and electrical properties of yttria-stabilized zirconia epitaxial thin films deposited by ion beam sputtering on silicon

Abstract

Thin films of yttria-stabilized zirconia (YSZ) have been grown on Si〈100〉 substrates by ion beam sputter deposition using an ultrahigh vacuum system with in situ diagnostic equipment (reflection high energy electron diffraction (RHEED) and Auger spectrometer). The crystalline quality of the films was determined by RHEED, X-ray diffraction and channelling of a 4He+ ion beam. The YSZ layers deposited within the 700–900°C temperature range under an oxygen partial pressure of about 10−4 Pa exhibited a monocrystalline cubic phase. The crystallographic continuity between the silicon substrate and the YSZ film estimated by channelling gives a χmin value of between 9.5% and 20%, depending on the deposition procedure. High frequency capacitance-voltage curves were measured for metal-YSZ-silicon capacitance. For a layer thickness of 0.3 μm, the accumulation capacitance gives a value of about 25 for the permittivity. The density of surface states at the YSZ-silicon interface determined by the Termann method is less than 1012 eV−1 cm−2 in the middle of the band gap with an increase near the conduction and the valence bands.