Epitaxial Growth of SrRuO3Thin Film Electrode on Si by Pulsed Laser Deposition

Pseudocubic SrRuO3 (100) epitaxial thin films were fabricated on Si (100) with a SrO buffer layer by pulsed laser deposition (PLD). Reflection high-energy electron diffraction (RHEED) revealed that the SrO layer is epitaxially grown on naturally oxidized Si substrates with an orientation relationship of SrO (110)/Si (100) and SrO //Si . Subsequent SrRuO3 deposition resulted in a (100) epitaxial thin film possessing good crystallinity with a full-width at half maximum (FWHM) of 1.9° in the SrRuO3 (200) rocking curve by X-ray diffraction (XRD). Based on the Gibbs free energy change in the reaction of silicon with alkaline earth metal oxides, deoxidization of SiO2 on Si by Sr is thought to play an important role in the epitaxial growth of SrO. Cross-sectional observation for the optimized SrRuO3/SrO/Si sample using transmission electron microscopy (TEM) revealed that the thickness of the SrO layer is less than 2 nm and that the SrRuO3 electrode forms an epitaxial thin film almost directly on Si.