Superconducting YBa2Cu3O7−δ thin films on Si (100) substrates with CoSi2 buffer layers by an in situ pulsed laser evaporation method

We have prepared high-quality c-axis oriented superconducting YBa2Cu3O7−δ thin films on Si (100) substrates with CoSi2 buffer layers by in situ pulsed laser ablation processing. The films were characterized by x-ray diffraction, four-point ac electrical resistivity, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. YBa2Cu3O7−δ films were found to be textured with c axis perpendicular to the substrate. A plot of normalized resistance against temperature exhibited a metallic behavior followed by an onset superconducting transition at 91 K with zero resistance temperature (Tc0) of 83 K. Cross-sectioned TEM results showed quite smooth interface between CoSi2 and Si with little interdiffusion; however, a reacted zone was observed between CoSi2 and YBa2Cu3O7−δ layers.