HYDROGEN RECYCLING IN CARBON-FILMS

Amorphous carbon films (∼40 nm thick) were prepared on the wall of a discharge vessel using methane plasma CVD. The films were exposed to a hydrogen and helium glow discharge. The hydrogen recycling phenomena in these films have been investigated. Measurements of the pressure change induced by the discharge allow the evaluation of hydrogen retention, and of hydrogen release. It has been found that the recycling depends on the wall temperature and on the energy of the hydrogen ions. The results are consistently interpreted in terms of a Desorbable-phase model) (D-phase moddl) with consideration of the dependence of the hydrogen depth profile in the films on the incident energy of the ions. © 1990.