Particle-induced desorption of hydrogen from a-C:H at low impact energies
The desorption of hydrogen from amorphous, hydrogen-containing carbon films (a-C:H) by low energy hydrogen (deuterium) and noble gas ions has been studied in an UHV test device coated with a-C:H films. The dynamics and quantities of the released fluxes, as well as the implanted fluxes by exposure to low energetic (200-350 eV) hydrogen and noble gas ions, have been measured. Evidence is presented for the preferential incorporation of low energy hydrogenic species in a growing a-C:H layer from CH(4)/H(2) mixtures. In subsequent RG discharges in pure hydrogen, the desorption of hydrogen from the film leads to a change of the recycling coefficient R from initial values greater than 1 to stationary values approximately equal to 1. The more effective removal of hydrogen by glow discharges in noble gases yields a strong receptivity for hydrogen of the a-C:H layer. This behaviour can be observed while operating a glow discharge in pure hydrogen following such a conditioning procedure. Starting reimplantation of hydrogen from values R less than 1, the a-C:H coating approaches a stationary state in which the hydrogen concentration is almost constant and the recycling coefficient again reaches values of about R = 1.
Bibliographic Reference: Article: Journal of Nuclear Materials, Vol. 176 & 177 (1990) pp. 319-325
Record Number: 199110872 / Last updated on: 1994-12-02
Original language: en
Available languages: en