Epitaxial growth of superconducting YBa2Cu3O7−x on Si(100) with CaF2 as intermediate buffer

Abstract

Epitaxial superconducting YBa2Cu3O7−x (YBCO) thin films have been grown on Si(100) using CaF2 as an intermediate buffer layer. The CaF2(100) layers were grown by molecular beam epitaxy while for the YBCO layers a laser ablation process was used. Electron channeling patterns of the YBCO surface show the characteristic four-fold symmetry for c-axis orientation. The epitaxial relationship is (001)YBCO//(001)Si and [010]YBCO//[110]Si. This corresponds to a lattice mismatch of only 1% in the a-b-YBCO interface plane. The 60-nm-thick layers are crack free. Magnetic shielding properties of the epitaxial YBCO layers have been studied by measuring the zero temperature penetration depth λab(0) and the power law dependence of the transition temperature versus magnetic field.

A Thin Film Approach to Engineering Functionality into Oxides

“…Although the structural quality of films of functional oxides grown on semiconductor substrates is far from the quality of these materials grown on appropriate oxide substrates, significant improvements have been made over the last seven decades (and especially in the last two decades) because oxides were first epitaxially integrated with semiconductors 296,297 . Several routes now exist for the epitaxial integration of functional oxides with semiconductors including (001) Si, 196,204,205,210,212–215,225,226,298–306 (001) Ge, 198,204,307,308 (001) GaAs, 304,309,310 (001) InP, 311,312 and (0001) GaN 226,313–315 . Using these routes a multitude of functional oxides, with conducting top and bottom electrodes when desired, have been epitaxially integrated with semiconductor materials 196,198,204,205,225,226,298,299,301,304,307–309,313,314,316–326 .…”

Epitaxial Calcium and Strontium Fluoride Films on Highly Mismatched Oxide and Metal Substrates by MOCVD: Texture and Morphology

“…[3][4][5][6] Besides, the structural properties and oxygen resistivity (even at high temperatures) of these compounds make them perfect buffer layer materials used for deposition of different classes of oxides onto semiconductors and other substrates. [7][8][9] At last, particular attention is paid toward the thin films of ionic insulators on metal surfaces. These systems are attractive for both technological applications such as fabrication of sensors, 10 resonant tunneling devices, 11 magnetic tunnel junctions, 12 and for fundamental studies of different physical phenomena occurring on the metal-insulator interface.…”

“…Inorganic fluorides have been intensively studied for a long time because they exhibit a number of unique properties that make them perfect materials for a wide range of potential applications, first of all, in optics and electronics. , Among them, special and very important materials are fluorides of alkaline-earth metals, in particular, CaF 2 and SrF 2 . They are dielectric and have a wide transmission range (from mid-infrared to vacuum ultraviolet) and extremely low refractive indices thus being very useful for microelectronic and optoelectronic devices, optical components (such as lenses, windows, prisms), optical coatings, multilayers, efficient optical filters, and waveguides. − Besides, the structural properties and oxygen resistivity (even at high temperatures) of these compounds make them perfect buffer layer materials used for deposition of different classes of oxides onto semiconductors and other substrates. − At last, particular attention is paid toward the thin films of ionic insulators on metal surfaces. These systems are attractive for both technological applications such as fabrication of sensors, resonant tunneling devices, magnetic tunnel junctions, and for fundamental studies of different physical phenomena occurring on the metal−insulator interface. , As one can see, many of these applications require fluorides in the form of good-quality thin films, grown epitaxially on appropriate substrate.…”