YBa2Cu3O7(YBCO) thin films were grown onSrTiO3substrates using a pulsed laser deposition system. The laser beam was scanned over the target in such a way to obtain a reproducible method of composition control at the substrate. In total, 17 films were grown under optimal conditions; they exhibited mean transition temperatures of 89.7±0.4 K and mean (005) rocking curve widths of 0.07°±0.02°. The narrowest (005) rocking curve width was measured to be 0.037°. Both the rocking curve line shapes and the dependence of transition temperature on rocking curve width suggest the films have single-crystal-like structure. ©1997 American Institute of Physics.