In-situ synchrotron study of growth of Y-Ba-Cu-O thin films on SrTiO3

The epitaxial growth of Y-Ba-Cu-O films on (100) SrTiO3 substrates in a sputtering system employing a faced magnetron gun has been studied in real time at the National Synchrotron Light Source facility. It is found that for a substrate temperature of 730 degrees C, the preferred orientation of film growth is very sensitive to the deposition rate: at a low rate (1 Angstrom/sec), the preferred growth is along the a-axis, while at a high deposition rate (6 Angstrom/sec), the preferred growth is along the c-axis. For a deposition rate (4 Angstrom/sec), the nature of the epitaxial growth is also dependent on the substrate temperature. The minimum epitaxial temperature of a-axis growth is around 685 degrees C. Below this temperature, an amorphous film is formed on the substrate surface. By following the peak shift in the θ-2θ scans as a function of the film thickness, we have observed., in real time, the d-spacing evolution. The rocking curves at different temperatures have also been measured to study the quality of the oxide films. For favorable conditions high quality crystalline films with a rocking curve width of less than 0.1 degree have been observed