Preparation and properties of in-situ YBaCuO films on Si substrates with buffer layers

High-T_c YBaCuO superconducting films have been prepared in-situ on Si substrates with buffer layers using off-axis single-target RF magnetron sputtering. A special cylinder heater with a reflecting cone was used to grow in-situ YBaCuO films on different buffer layers, such as Y-stabilized ZrO₂ (YSZ), LaAlO₃, LaGaO₃, NdAlO₃, NdGaO₃, SrTiO₃ , and MgO. The YBaCuO films on YSZ and LaAlO₃ buffer layers have T_c(zero) of 84 K and 83 K, respectively. Films deposited at substrate temperatures above 650°C have preferential orientation with c-axis perpendicular to the film surface. The films also show excellent surface smoothness up to atomic scale with a roughness of 5 Å. The qualities of the films as well as the dielectric properties of the substrate and buffer layers are favorable for microelectronic applications, especially for high-frequency applications. High-T_c microbridges have been fabricated using the films