High-quality YBa2Cu3O7−<i>x</i> thin films by plasma-enhanced metalorganic chemical vapor deposition at low temperature

Abstract

Single-crystalline epitaxial YBa2Cu3O7-x thin films with a sharp superconducting transition temperature of 90 K and a critical current density of 3.3×106 A/cm2 at 77 K were prepared by a plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD) process. The films were formed in situ on (100) LaAlO3 substrates at a temperature of 670 °C in 2 Torr partial pressure of N2O. X-ray analysis indicated that films grew epitaxially with the c-axis perpendicular to the substrate and the a and b axes uniformly aligned along the LaAlO3 [100] directions. High-resolution transmission electron microscopy along with electron diffraction revealed that the films grew epitaxially with atomically abrupt film-substrate interfaces. The high degree of epitaxial crystallinity of the films was also confirmed by Rutherford backscattering spectroscopy which gave a minimum channeling yield of 9%.