Formation and characterization of the fluorocarbonated-SiO2 films by O-2/FTES-helicon plasma chemical vapor deposition

Abstract

Fluorocarbonated-SiO2 films were prepared on a p-type Si(100) substrate using FSi(OC2H5)(3) (FTES) and O-2 mixture gases by a helicon plasma source. High density O-2/FTES/Ar plasma of similar to 10(12) cm(-3) is obtained at low pressure (<3 mTorr) with RF power above 900 W in the helicon plasma source where the FTES and O-2 gases are greatly dissociated. The fluorocarbonated-SiO2 film deposited in the helicon plasma chemical vapor deposition contains C-F bonds which are not found in the fluorocarbonated-SiO2 film made by thermal chemical vapor deposition, where the FTES and O-2 react chemically on the substrate. Fourier transform infrared and X-ray photoelectron spectroscopy spectra show that the film has Si-F, Si-O, and C-F bonds. The Si-F and C-F bonds may lower the dielectric constant greatly. The relative dielectric constant, leakage current density, and dielectric breakdown voltage are about 2.8, 8 x 10(-9) A/cm(2), and >12 MV/cm, respectively. However the dielectric constant and leakage current density of the film annealed at 500 degrees C are about 3.2 and 9 x 10(-11) A/cm(2), respectively. The step-coverage of the deposited fluorocarbonated-SiO2 film in 0.3 mu m metal pattern is about 91%. (C) 1999 Elsevier Science S.A. All rights reserved.