Epitaxial growth of Y Ba2Cu3O7−δ thin films on silicon-on-insulator substrates by pulsed laser deposition

Abstract

High quality superconducting Y Ba2Cu3O7−δ (YBCO) thin films have been successfully deposited on silicon-on-insulator(SOI) substrates buffered by an yttria-stabilized zirconia (YSZ) layer usingthe in situ pulsed laser deposition (PLD) method. X-ray diffraction (XRD)θ–2θ-scanand φ-scan, and reflection high energy electron diffraction (RHEED), indicate that both theYSZ and YBCO thin films are of high crystallinity and good lattice orientation.Atomic force microscopy (AFM) shows that the root mean square roughnessRq of YSZ thin films is less than 0.9 nm in an area of1 µm × 1 µm, and that of YBCO thin films is about 3 nm in an area of2 µm × 2 µm. The zero-resistancetemperature TC0 of the YBCO/YSZ/SOI multilayers is up to 88 K, measured by a four-probe method.However, scanning electron microscopy (SEM) demonstrates many clear cracks in YBCOthin films due to the lattice constant and thermal expansion coefficient mismatch betweenSOI and YBCO. The crack width changes with the thickness of YBCO thin films.