Abstract
The time-averaged sheath drops across the sheath in front of a powered electrode have been determined using the gridded energy analyzer, by estimating the maximum energy of the ions accelerated by the sheath potential. It is observed that from pressure p=0.01 to 1 Torr, the sheath drops decrease slightly with operating pressure, and above p=0.1 Torr, the sheath drops exhibit a sharper decrease. Also, the sheath drops increase sharply with R.F. power input. These results could be explained qualitatively in terms of the variation of R.F. voltage amplitude with pressure and R.F. power.