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An experimental study on the ion impact energy distribution and the total ion flux at the driven electrode of a parallel plate reactive ion etcher is presented. Results are shown for 13.56 MHz discharges in Ar, Ar/H2, N2, O2, Cl2, and SF6/He over a pressure range of 0.3–40 Pa. The ion impact energy distribution consists of a collision-free part and a collision-induced part. It is observed that in Ar, N2, O2, and Cl2 the collision-induced part contains single and double peaks at regular energy intervals. This peaked structure is attributed to charge exchange processes in the sheath. Both the collision-free part and the collision-induced part of the ion impact energy distribution are well described by a model based on a constant sheath width, a sinusoidal sheath voltage, and a power law for the electric field in the sheath. The only adjustable parameter in the model is the sheath thickness. The sheath thickness has also been determined independently from the total ion current density using the Child–Langmuir law. The obtained values are in good quantitative agreement with each other and with the observed optical sheath thickness, demonstrating the overall consistency of the present approach.

A numerical study on the ion and neutral angular impact energy distribution at the i-f-driven electrode of a reactive ion etcher is presented. The calculations for the ions are performed using a Monte Carlo method that includes charge exchange and elastic scattering. The contribution of both collision processes to the angular ion impact energy distribution is studied. For the case that charge exchange is the only collision process, the Monte Carlo results can be checked against those of a method based on a spatially uniform and time independent collision rate. In that case, both methods yield the same ion impact energy distribution. The position, velocity, and propagation angle of the energetic neutrals created in collisions of ions with the background gas are stored. These are used as input data for a separate code that follows the evolution of the angular neutral energy distribution, taking into account (multiple) neutral elastic scattering. From the ion and neutral distributions, the number of neutrals per ion, the average impact energy, and the energy-weighted average impact angle have been derived. It is shown that these parameters are well described by simple expressions. Finally, the sputter yield is calculated. The results show that the contribution of the angular distributions of both ions and neutrals to the yield can be neglected.

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