One goal of this work was to develop a reproducible method of preparing high quality Y‐Ba‐Cu‐O superconducting films and to study their properties versus thickness. This was accomplished by rf diode sputtering from a single target. Twenty‐seven depositions were made using a target containing 8.9‐at. % Y, 37.3‐at. % Ba, and 53.8‐at. % Cu. Film thicknesses ranged from 0.09 to 2.4 &mgr;m. The film compositions obtained were 15.6±1.0‐at. % Y, 35.8±1.0‐at. % Ba, and 48.7±1.7‐at. % Cu for the mean and standard deviation. The films were amorphous as‐deposited and crystallized by annealing in O2at 915 °C. X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy indicated that, on (100)SrTiO3substrates, films with thickness less than ∼0.25 &mgr;m were epitaxially oriented with theircaxis perpendicular to the substrate. Films on (110)SrTiO3were oriented with theircaxis parallel to the substrate. On (100)SrTiO3, zero resistance was achieved in 30 samples from 27 runs at 85.6±1.4 K with a transition width (10%–90%) of 1.8±1.1 K independent of thickness. Results for deposition on a variety of other substrates were more variable. Diamagnetic shielding of up to 38% was calculated from the initial slope ofMvsH. This low value was attributed to the presence of second phases and a significant diffusion layer thickness, both observed by transmission electron microscopy. Critical currents, measured by transport using a four‐point probe, reached 8.1×105A/cm2at 77.35 K for a 0.2‐&mgr;m film deposited on (100)SrTiO3. Comparable values were obtained by calculation from theM‐Hhysteresis loop, from which we infer that there are either continuous epitaxial sheets ofcaxis oriented 123 or, if there are grain boundaries, the coupling across them is strong.