[en] Scanning tunnelling microscopy (STM) is applied to investigate the surface structure of high-quality c-axis oriented laser-ablated thin YBa₂Cu₃O_7-δ films. The main features of the surface are steps of one-unit cell height documenting the two-dimensional growth process of the epitaxial film. For the first time atomic resolution with STM is achieved, indicating a 3.8 A square lattice on YBa₂Cu₃O_7-δ laser-ablated films, as expected from diffraction techniques. Screw dislocations and holes of different sizes are the most frequently observed types of lattice defects in these films