The properties of SiO2films deposited in a remote plasma enhanced chemical vapor deposition (RPECVD) process with chlorine addition into the SiH4–N2O reactants has been studied. With Cl2addition, the interface trap density (located at ∼Ev+0.3–0.35 eV) was decreased and strained silicon bonds were relaxed. As chlorine partial pressure and deposition temperature were increased, however, porosity and surface roughness of the film were increased due to the formation and desorption of Si–Cl or O–Cl bonds. ©1995 American Institute of Physics.