High quality superconducting YBa 2 Cu 3 O 7−δ (YBCO) thin films have been successfully deposited on silicon-on-insulator (SOI) substrates buffered by an yttria-stabilized zirconia (YSZ) layer using the in situ pulsed laser deposition (PLD) method. X-ray diffraction (XRD) θ -2θ -scan and ϕ-scan, and reflection high energy electron diffraction (RHEED), indicate that both the YSZ and YBCO thin films are of high crystallinity and good lattice orientation. Atomic force microscopy (AFM) shows that the root mean square roughness R q of YSZ thin films is less than 0.9 nm in an area of 1 µm × 1 µm, and that of YBCO thin films is about 3 nm in an area of 2 µm × 2 µm. The zero-resistance temperature T C0 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 YBCO thin films due to the lattice constant and thermal expansion coefficient mismatch between SOI and YBCO. The crack width changes with the thickness of YBCO thin films.

Superconducting Tl2Ba2CaCu2O8 thin films (Tl-2212) have been reproducibly fabricated on both sides of 2 inch LaAlO3(001) substrates by using a so-called two-step process. A simple and flexible horizontal arrangement inside the crucible during thallination has been proposed, to ensure a good convection of thallous oxide vapor around the film surface, and thus a high film quality on both sides. A good uniformity over the whole area of the films has been realized. The films are strongly textured, with the c-axis perpendicular to the substrate surface, and they show the fourfold symmetry of the tetragonal crystal structure. The full width at half maximum of the (002) peak for both films on the best sample is 0.43° and 0.55° respectively. The films exhibit flat terraces with particles and shallow holes, but free of microcracks. The superconducting critical temperatures fall in the range 105–108.5 K. The critical current densities are between 1.0 × 106 and 4.8 × 106 A cm−2 at 77 K. The microwave surface resistances at the central area of the films are around 500 μΩ at 77 K and 10 GHz. These films are suitable for microwave applications.