HYDROGENATING SILICON DIOXIDE IN AN ELECTRON-CYCLOTRON PLASMA

The hydrogenating effect of a low-temperature, electron cyclotron reso nance excited H-2 plasma on the surface chemistry of thermal SiO2 film s is analyzed in situ by x-ray photoemission spectroscopy and static s econdary ion mass spectrometry. Hydrogenation with this nominal 10 eV proton flux results in Si-(O4), H-Si-(O3), (H-2)-Si-(O2), (H-2)-Si-O, and H-Si-(Si3) bonding states to the complete exclusion of Si-OH bond formation. A simple thermodynamic argument accounts for the exclusivit y of Si-H bonds terminating the outermost (O3)-Si-O-Si-(O3) network of a thick SiOx<2 film, thereby transforming what is normally a hydrophi lic surface into one that is hydrophobic.