The growth of YBa2Cu3O7-x thin films deposited by sputtering onto (111) SrTiO3 substrates at different temperatures, T-s, was studied by X-ray diffraction and HRTEM measurements. At all T-s values, the films grow epitaxially (113) oriented. Ar low T-s, the growth is pseudomorphic and homogeneously strained. At high T-s, strain is released probably by defect incorporation leading to broad mosaic distributions. In the intermediate T-s range, internal strain is accumulated in the films. Three domain orientations tilted by 120 degrees were observed in the film plane. Superconductivity with maximum T-c values of 84 K was only observed in films prepared at high T-s revealing the orthorhombic structure. The oxygenation of the films is probably strain-controlled.