A planar method for patterning of high-temperature superconducting films and multilayers

We present a novel technique for patterning high-temperature superconducting (HTS) film and multilayer device structures. In the process an impurity ion (e.g., Si) is implanted into HTS films through a photoresist mask. The impurity ions convert the irradiated portion of the film into an insulating form by chemical reaction between the ions and the oxygen in the film, without altering the overall crystalline structure of the film. Removal of the photoresist results in a flat surface, which allows the epitaxial growth and implantation patterning of subsequent films so that a complete multilayer device structure can be fabricated. We show in detail the patterning process, as well as the properties of patterned and regrown films. Some simple device structures, such as a vertical contact and a crossover, are demonstrated.