Modelling and experimental validation of capacitively coupled plasmas in hydrogen
Résumé
Parallel plate capacitively coupled plasmas (CCPs) are commonly used for material processing applications such as deposition and etching of thin films. Since hydrogen is the most abundant component used as a diluent in a variety of gas mixtures, pure H2 plasma dynamics is to be investigated first. A one-dimensional in space, three-dimensional in velocity hybrid model described in detail in [1-3] was used to investigate CCPs in H2. The hybrid model couples self-consistently a particle-in-cell model with Monte Carlo collisions for charged species (electrons, H , H2 , H3 and H− ions), with a reactiondiffusion fluid model for neutrals (14 vibrational levels of the electronic ground state of H2, and H atoms). In the past, the model was compared with experimental results found in literature for the classical sinusoidal voltage [1, 2] and, more recently, it has been used in several combined computational-experimental studies to investigate plasmas sustained by tailored voltage waveforms (TVWs) composed of multiple harmonics [3, 4]. The excitation dynamics and ion flux asymmetry and many quantities of paramount importance for plasma processing, including the ones not accessible through experimental investigations, have been analysed for different TVWs, thus allowing an improvement of the model and giving a better insight into this very new kind of discharge excitation. References [1] P. Diomede, M. Capitelli, S. Longo, Plasma Sources Sci. Technol., 14, 459-466 (2005) [2] P. Diomede, S. Longo, D. J. Economou and M. Capitelli, J. Phys. D: Appl. Phys., 45, 175204 (14pp) (2012) [3] P. Diomede, D. J. Economou, T. Lafleur, J.-P. Booth and S. Longo, Plasma Sources Sci. Technol., 23, 065049 (11pp) (2014) [4] B. Bruneau, P. Diomede, D. J. Economou, S. Longo, T. Gans, D. OConnell, A. Greb, E. Johnson, J.-P. Booth, submitted to Plasma Sources Sci. Technol.