Fluorine-doped tin oxide films on glass substrates have been prepared by reactive magnetron DC-sputtering in Ar-O2-Freon plasma from a metallic tin target. We studied the relationship between the discharge characteristics and film properties and found the discharge conditions in which the films belong tot he SnO2 or to the SnO stoichiometry, by proposing a phase diagram for this system. It was shown that the film stoichiometry is closely related to the tin valence changes at the target. We found that there is a narrow voltage band and a limit value in the oxygen content where the films have SnO2 stoichiometry; outside this region SnO films are obtained. We studied the crystallinity and the optical properties of the SnO2 films. The results show that crystalline films have cassiterite-like diffraction patterns with preferred orientation in the 100 planes.
