Superconducting thin films of FeySe1-xTex have been successfully grown on a variety of single-crystal substrate materials by radio frequency sputtering, and the effect of processing conditions on the microstructural development and superconducting properties has been investigated. The degree of unit cell anisotropy (c/a ratio), which is known to be linked to the superconducting transition temperature, is found to be sensitive to both Te and Fe content. However, the Te and Fe content cannot be varied independently, as the stable concentration of excess Fe is found to increase with Te content. Large scale compositional variations are found to exist in some samples, and it is believed that sub-micron scale chemical inhomogeneities are present in all samples. Post-deposition heat treatments carried out on the thin films indicate that the ternary Fe(Se, Te) phase is not very thermodynamically stable, partially transforming into Fe(Se, Te)(2) upon heating at modest temperatures for short times.