Growth of Biaxially-Textured MgO Buffer Layers by Inclined Substrate Deposition

Abstract

MgO buffer layers were grown by Inclined Substrate Deposition (ISD) for superconducting coated conductors. The surface structure, texture, and extended defects were analyzed for films with different MgO layer thicknesses. A roof-tile structure was only observed for films with layer thicknesses exceeding 800 nm. MgO facet widths and amplitudes were determined for different MgO buffer layer thicknesses. At 800 nm the facets height was 18 nm and the facet width was 71 nm. The corresponding values measured for a 5 μm thick MgO film were 64 nm and 234 nm, respectively. For layers with layer thicknesses smaller than 200 nm the films were polycrystalline with a grain size of 20 nm. For larger layer thicknesses the ISD MgO film grew in the form of columns with diameter of 50 to 100 nm. The texture of the layers was analyzed by electron diffraction in the TEM. From radial intensity profiles obtained from electron diffraction patterns the background-corrected (002)/(111) intensity ratio was extracted. It was found that the (002)/(111) intensity ratio allows to quantify the degree of texture.