THE DEPOSITION OF SIOF FILM WITH LOW DIELECTRIC-CONSTANT IN A HELICONPLASMA SOURCE

SiOF films deposited by a helicon wa lie plasma chemical vapor deposit ion method has been characterized using Fourier transform infrared spe ctroscopy and ellipsometry. High density plasma of > 10(12) cm(-3) can be obtained on a substrate at low pressure (< 10 mTorr) with rf power > 400 W with a helicon plasma source. A gas mixture of SiF4, O-2, and Ar was used to deposit SiOF films on 5 in, Si(100) wafers not intenti onally heated, Optical emission spectroscopy was used to study the rel ation between the relative densities of the radicals and the depositio n mechanism. It was found that the addition of Ar gas to the SiF4/O-2 mixture greatly increased the F concentration in the SiOF film, Discha rge conditions such as gas composition, sheath potential, and the rela tive densities of the radicals affect the properties of the film. The dielectric constant of the SiOF film deposited using the helicon plasm a source was 3.1, a value lower than that of the oxide film by other m ethods. (C) 1996 American Institute of Physics.