Superconducting stoichiometric YBa2Cu3O7−xfilms have been grown by rf sputtering of a single bulk material target in an Ar+10% O2sputtering atmosphere on a variety of substrates. Films on SrTiO3substrates exhibited the best post‐annealing superconducting properties with the critical onset temperature of 90 K and zero resistance at 67 K. The maximum current density for these samples was 1×105A/cm2at 4.2 K. An extensive loss of film underneath the target was observed during the growth of these films which can be attributed to resputtering due to oxygen anion or energetic neutral particle bombardment of the substrate.