Patterning of high Tc superconducting thin films on Si substrates

Abstract

Interdiffusion and reaction at the interface between an YBaCuO film and a Si substrate degrade the superconductivity of the film. Using a buffer layer, the film-substrate interaction can be reduced. Thus, a superconducting thin film is formed on a silicon substrate. We have developed a new method of patterning superconducting thin films based on the Si-YBaCuO intermixing. On a silicon substrate, a thin layer of noble metal was first evaporated and patterned using photolithography. An YBaCuO film was then deposited by e-beam evaporation and annealed in a rapid thermal processing system. After a high temperature annealing, the patterned feature became superconducting separated by Si-YBaCuO intermixed areas. We have demonstrated superconducting micron-sized line structures with T c of 73 K. This patterning technique may be useful for making high T c superconducting interconnects and devices on a Si wafer.