Cu-O-N layers were deposited on Si-[100] wafers at a temperature of 90 degrees C in a reactive magnetron sputtering ion plating system (R-MSIP). For this, a Cu-target was sputtered by a nitrogen/oxygen plasma, and the influence of the oxygen partial pressure on composition, structure, and texture of the Cu-O-N layers was investigated. The analyses of the films with EPMA, XRD, and HEED yielded the following results : with an appropriate setting of the oxygen partial pressure, the oxygen content of the Cu-O-N layers could be controlled between 2.4 and about 50 at. %. Structure analyses have shown changes in the crystal structure of the films with increasing oxygen and decreasing nitrogen content from the simple cubic (sc) structure of Cu3N, followed by a two phase region, where the sc structures of Cu3N and Cu2O appear, to a single phase film with the sc structure of Cu2O. With an oxygen content of 43.6 at. % a new Cu-O-N phase with the tetragonal structure of paramelaconite (approximate to Cu122+Cu4+O14) and the composition Cu27O22N was grown. The film with an oxygen content of about 50 at. % consists of monoclinic CuO.