MICROSTRUCTURAL DEPENDENCE OF SPUTTERED YBA2CU3O7-X THIN-FILMS ON DEPOSITION PARAMETERS

An extensive characterization study of sputtered YBa2Cu3O7-x thin film s deposited on single-crystal (001) LaAlO3 substrates was carried out using electron-microscopy techniques to investigate the effect of the deposition parameters on the microstructure of the films. The research focused mainly on the study of the phases present in the film and the orientation and morphology of the grains. The film microstructure was found to be strongly dependent on the atomic mobility during depositi on. Lower deposition temperatures and higher oxygen partial pressures led to a lower mobility of atoms favoring smaller grain sizes, larger a-axis coverage and a higher density of stacking faults. A computer mo del was developed to simulate the microstructural development in the f ilm. With the use of this model, the nucleation density of a-axis grai ns was found to range from 10(7) to 8 X 10(11) nuclei/cm2.