HYDROGEN INCORPORATION IN DUAL-MODE PECVD AMORPHOUS-SILICON OXIDE THIN-FILMS

Hydrogen incorporation in amorphous silicon oxide thin films a-SiOx:H (0.5 < x < 2.0) was studied quantitatively by combining nuclear analys is (Rutherford backscattering spectrometry (RBS) and elastic recoil de tection analysis (ERDA)) and IR absorption spectroscopy. The films wer e obtained at low temperatures (40-250 degrees C) and high growth rate s (R(d)) up to 55 Angstrom s(-1) using a dual-plasma-enhanced chemical vapour deposition (dual-PECVD) reactor. Hydrogen atoms were bonded to Si in Si-rich films, whereas in nearly stoichiometric films H atoms w ere only bonded to oxygen in Si-OH and H2O configurations. The intensi ty of the OH broad absorption band increased for films produced at low temperatures and high oxygen flow rates (high deposition rates). No m odification of the spectrum was observed after thermal annealing at 25 0 degrees C, even for thin films deposited at 70 degrees C, indicating good stability of the bonded H. Quantitative analysis of the stoichio metry of the films was undertaken, and the proportionality constants b etween the atomic concentration and the integrated absorbance for Si-O -Si, Si-O-H and H-O-H stretching modes and the H-O-H bending mode are given.