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Global kinetic models combined with Monte Carlo sheath models are developed for SF 6 and C 4 F 8 plasma discharges for silicon etching under the Bosch process. In SF 6 plasma, the dominant positive ions are SF + 5 , SF + 4 , SF + 3 and F + while in C 4 F 8 the dominant positive ions are CF + 3 and C 2 F + 3 . The simulation results show that the electrical parameters, such as the electron density and electron temperature, clearly affect the sheath dynamics and consequently the ion energy distribution function evolutions. In this context, we showed the effects of the operating conditions, such as the pressure and the radiofrequency power, on the electron density and electron temperature evolutions as well as the reactive particle fluxes (neutral and positive ions) involved in the plasma surface interactions for etching/deposition under the Bosch process. Ion energy distribution functions obtained from SF 6 and C 4 F 8 plasmas are compared with each other as regards the electrical properties of their associated plasmas. The simulation results show that the bimodal peaks of ion energy distribution functions are wider for SF 6 plasma than for C 4 F 8 plasma due to the high sheath thickness of SF 6 compared to that of C 4 F 8 . This is explained by the low electron density due to the high electronegativity of SF 6 in comparison to that of C 4 F 8 . The simulations also reveal that the bimodal peak of the ion energy distribution function is wider when the ion mass is low.

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