DEPOSITION ANGLE-DEPENDENT MORPHOLOGY OF LASER-DEPOSITED YBA2CU3O7 THIN-FILMS

Surface morphology of pulsed laser deposited YBa2Cu3O7 films have been studied as a function of the plume angle with respect to the substrate's normal. All the films showed c-oriented epitaxial growth according to x-ray diffraction analyses, and T(c)(R=0) greater-than-or-equal-to 88 K and J(c) greater-than-or-equal-to 10(6) A/cm2 at 77 K. Surface morphology, types of particles, and their number density, changed drastically with the deposition angle. As the angle was changed from O-degrees to 90-degrees, particle type was changed from larger droplets to much smaller outgrowths with a gradual number density change. While larger droplets had the same composition as the target in accordance with their direct flight origination, smaller outgrowths were Cu rich and were believed to be byproducts of the locally inhomogeneous reaction of the ablated species resulting from their highly anisotropic momenta on the surface. High angle films were also found to contain a-oriented grains.