Characterization of ZrO₂ Buffer Layers for Sequentially Evaporated Y-Ba-Cu-O on Si and Al₂O₃ Substrates

Abstract

A large variety of techniques have been employed for the formation of thin films of the high temperature superconducting oxides on many different substrates. These efforts have been driven by the desire to investigate and develop electronic applications of these materials. Several of the substrates that have been used possess undesirable electronic properties, such as the large dielectric constant of SrTiO₃. For many applications it is desirable to obtain the superconducting films on silicon or, for high frequency applications, on substrates such as Al₂O₃ or GaAs. Unfortunately, the deleterious interactions between the films and these substrates or common dielectrics¹, such as silicon dioxide, result in unacceptable degradation of both the superconductor and the substrate. This has led to the investigation of the use of thin films of materials such as ZrO₂ ² or silver³ as buffer layers between the superconductor and the substrate.