Characterization of Stable Fluorine-Doped Silicon Oxide Film Prepared by Biased Helicon Plasma Chemical Vapor Deposition

Abstract

Fluorine-doped silicon oxide (SiOF) film prepared by biased helicon plasma chemical vapor deposition with SiF₄ and O₂ is characterized. In this characterization, the SiOF film is compared with that prepared using a nonbiased plasma. SiOF films prepared using a biased plasma are stable in air. Whereas films prepared using a nonbiased plasma are not stable in air and the relative dielectric constant and stress vary in the ranges 3.2 to 3.5 and from -35 MPa to 0 MPa, respectively. Analysis Fourier transform infrared (FT-IR) and thermal desorption mass spectroscopy (TDS) spectra, clarifies the following. (1) Si-F bonds are formed in SiOF films prepared using a biased plasma. (2) Not only Si-F bonds but also F-Si-F bonds are formed in SiOF films prepared using a nonbiased plasma. (3) The F-Si-F bond structure formed in SiOF films absorbs water easily.