N <sub>2</sub> –H <sub>2</sub> capacitively coupled radio-frequency discharges at low pressure: II. Modeling results: the relevance of plasma-surface interaction
Miguel Jiménez-Redondo, Audrey Chatain, Olivier Guaitella, Guy Cernogora, Nathalie Carrasco, L. L. Alves, L. Marques
Abstract
Abstract In this work, we present the results of simulations carried out for N 2 –H 2 capacitively coupled radio-frequency discharges, running at low pressure (0.3–0.9 mbar), low power (5–20 W), and for amounts of H 2 up to 5%. Simulations are performed using a hybrid code that couples a two-dimensional time-dependent fluid module, describing the dynamics of the charged particles in the discharge, to a zero-dimensional kinetic module, that solves the Boltzmann equation and describes the production and destruction of neutral species. The model accounts for the production of several vibrationally and electronic excited states, and contains a detailed surface chemistry that includes recombination processes and the production of NH x molecules. The results obtained highlight the relevance of the interactions between plasma and surface, given the role of the secondary electron emission in the electrical parameters of the discharge and the critical importance of the surface production of ammonia to the neutral and ionic chemistry of the discharge.