Sputter deposition of YBa₂Cu₃O_7-x films on Si at 500°C with conducting metallic oxide as a buffer layer

Superconducting YBa₂Cu₃O_7-x thin films were deposited on Si substrates at 500°C by rf magnetron sputtering from a stoichiometric oxide target. Metallic oxide RuO₂, sputtered by reactive dc magnetron, was used as a buffer layer to nucleate the superconducting film and minimize the reactions between Si and superconductor. The as-deposited thin films, without further post high-temperature annealing, were completely superconductive at 79 K. Very smooth surface morphology was demonstrated by scanning electron microscopy. X-ray diffraction data indicated that the films had a randomly oriented polycrystalline structure. Auger electron spectroscopy did not reveal interdiffusion of elements in the three layers.