Effects of RF power on low-pressure inductively coupled plasma of hydrogen and trans-two-butane

The hydrocarbon glow discharge polymer (GDP) shells fabricated by plasma polymerization technology were used as the ablators for ICF targets. In order to understand the properties of hydrocarbon plasma for GDP deposition, plasmas of trans-two-butane and H2 (T2B/H2) were investigated by Langmuir probe and mass spectrometer in the diffusion region. Several parameters, such as electron energy probability functions, electron densities, electron temperature were analyzed. The relationship between the properties of plasma and the discharge parameters were also discussed. It was found that there was a significant modulating effect of the radio frequency (RF) powers on the plasma parameters. The electron density was found to be nearly proportional to the discharge power in the range of 10 W to 35 W. As the RF power increased, the electron temperature and plasma potential decreased at first then increased with discharge power, which was governed by a two-step ionization mechanism. The small and stable fragments, found by mass spectrometer, indicated that the polymerization was suppressed in the gas phase at high RF power.