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Heteroepitaxial Y2O3 films were grown on oxidized and clean Si (100) surfaces by ion assisted evaporation under an ultrahigh vacuum. The crystalline structure, crystallinity, morphology, and electrical properties were investigated using various techniques. The crystallinity assessed by x-ray diffraction and Rutherford backscattering spectroscopy shows that the films grown on the oxidized Si substrates have better crystallinity and smoother morphology compared to those on the clean Si. As the annealing temperature increases, the crystallinity and morphology are stable for the films grown on the oxidized Si, while those of the films grown on clean Si substrates degrade. The difference between the two films is attributed to the formation of hillocks and a chemical reaction at the interface between the film and SiO2. The low crystallinity, strain change, and the reaction of excess Y in the films grown on the clean Si contribute to the crystalline structure and the formation of hillock. These changes of crystallinity and morphology show that the films grown on the oxidized Si surface are more suitable for device applications. Thus, the films grown on the oxidized Si result in higher breakdown field strength and lower trap charge density than those on clean Si after the annealing treatment.

YSi 2−x films were grown by ion-assisted evaporation in an ultrahigh vacuum (UHV) on Si(111) through a thin SiO2 layer. The films grown on the oxidized Si were changed from a polycrystalline structure with various phases of oxides and silicides into a single-crystalline silicide structure as the annealing temperature was increased in the UHV chamber. The structural change with the annealing temperature implied that various Y2O3 phases formed by the reaction between Y and SiO2 were decomposed and transformed into YSi2−x under the UHV environment. Rutherford backscattering spectroscopy/channeling showed that, although the interfacial crystallinity of the film grown on the SiO2 layer was poorer quality than the film grown on a clean Si surface, a single crystalline YSi2−x layer with high crystallinity (χmin=8%) was grown. These results showed that the difference of the thermal energy and the formation energy between the oxides of Y2O3−SiO2 and yttrium silicide determined the evolution of the silicide layer formation and its crystal structure.

Pb(Zr0.52Ti0.48)O3 (PZT) thin film on Pt/RuO2 double electrode was successfully prepared by using a new alkoxide-alkanolamine, sol-gel method. It was observed that the use of Pt/RuO2 double electrode reduced leakage current, resulting in a marked improvement in the leakage characteristics and more reliable capacitors. Typical P-E hysteresis behavior was observed even at low applied voltage of 5 V, manifesting greatly improved remanence and coercivity. Fatigue and breakdown characteristics, measured at 5 V, showed stable behavior, and no degradation in polarization was observed up to 1011 cycles.

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