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1987
Conference Paper
Titel
Network structure and thermal decomposition of plasma deposited a-C/H films studied by gas effusion spectroscopy
Abstract
Hydrogenated amorphous carbon films, deposited onto negatively biased substrates in a 13.56 MHz hydrocarbon glow discharge system, have been investigated by mass spectroscopic thermal effusion measurements. Depending on the bias voltage, U sub B, as the most important deposition parameter, hydrocarbons and/or H2 molecules are desorbed at threshold temperatures between 300 degrees C and 600 degrees C. The threshold temperature increases with increasing bias voltage while the mass of the desorbed molecules decreases. Using double layer a-C:H/a-C:D films, it is shown that H2 and CH4 molecules are formed in the volume of the film followed by molecular diffusion through the a-C:H network. For high bias voltages (U sub R is equal or bigger than 500 V), the reduced pore size of the strongly cross-linked a-C:H network is shown to prevent diffusion of hydrocarbon molecules, while the films are still permeable for hydrogen. (IAF)
Author(s)