  The electronic anisotropy in MgB2, is still a not completely clear topic;
high quality c-oriented films are suitable systems to investigate this
property. In this work we present our results on MgB2 superconducting thin
films grown on MgO and sapphire substrates. The films are deposited in high
vacuum, at room temperature, by Laser Ablation, starting from two different
targets: pure Boron and stoichiometric MgB2. In both cases, to obtain and
crystallize the superconducting phase, an ex-situ annealing in magnesium vapor
is needed. The films were characterized by Synchrotron radiation diffraction
measurements; the films turned out to be strongly c-oriented, with the c-axis
perpendicular to the film surface and an influence of the substrate on
crystallographic parameters is observed. Resisivity measurements with the
magnetic field perpendicular and parallel directions to the film surface
evidenced an anisotropic upper critical field behavior. The Hc2 ratios (h)
resulted in the range 1.2-1.8; this difference will be discussed also in
comparison with the literature data.
