HYDROGEN AND DEUTERIUM MIGRATION IN ANNEALED PLASMA-DEPOSITED SILICON-NITRIDE FILMS

The incorporation of hydrogen in nearly stoichiometric silicon nitride deposited by plasma enhanced chemical vapour deposition is investigat ed by infrared spectroscopy. During the deposition, deuterium is added to the silane, nitrogen and helium mixture. After annealing up to 100 0 degrees C, some films show a very large increase of the 2200 cm(-1) absorption peak. We conclude from analysis of isotopic substitution th at the free hydrogen atom does not contribute to building new Si-H bon ds. This result agrees with our previous conclusion on a continuous an d large change in the oscillator strength of the Si-H stretching mode.