Ion energy analysis through rf-electrode

Energy measurements of ions which impinge on an rf-electrode in plasma were taken using two modes, a de-mode and an rf-mode. We calculated the ion energy distributions which were obtained using these modes and found that, for the de-mode, the energy distribution broadened, and the center of the distribution varied, depending on the mass number of the ion. The distribution had extra peaks in addition to the normal saddle-shaped peaks. The features of the calculated distribution agreed well with the experimental results. The rf-mode was necessary to obtain the correct ion energy at the rf-electrode.