The effect of fluorine onSiO2films was investigated by comparing chemical and electrical properties of fluorinated silicon oxide (SiOF) films with those ofSiO2films. The SiOF films were prepared at room temperature by plasma enhanced chemical vapor deposition incorporatingCF4as the fluorine source into the deposition process of theSiO2films usingSi2H6andN2O.The relative dielectric constant of the as-depositedSiO2films was reduced from 5.95 to 4.43 by the incorporation of fluorine and with postmetallization anneal. The breakdown measurements on the SiOF films showed no early failures at a field strength of⩽3 MV/cm,resulting in an average breakdown field strength of 7.11 MV/cm. ©1998 American Institute of Physics.