Effects of deposition temperature on the microstructure of MOCVD Y₁Ba₂Cu₃O_7-x thin films

The effects of deposition temperature on the microstucture and composition of Y₁Ba₂Cu₃O_7-x films deposited on MgO and SrTiO₃ substrates by the metal-organic chemical vapour deposition (MOCVD) method were investigated. As the deposition temperature decreased from 900 to 700 °C, the Cu content in the deposited film increased. SEM micrographs of the films showed that the growth direction of the film was changed from c axis to a axis perpendicular to the substrate surface, and then to random orientation, as the deposition temperature decreased. The superconducting transition temperature and the transition width of films deposited on SrTiO₃ substrates at temperatures higher than 810 °C were over 90 K and within 1 K, respectively.