ION ENERGY AND ANGULAR-DISTRIBUTIONS IN INDUCTIVELY DRIVEN RADIO-FREQUENCY DISCHARGES IN CHLORINE

In this article, we report values of ion energy and angular distributi ons measured at the grounded electrode of an inductively coupled disch arge in chlorine gas. The inductive rf drive in our cell produced high plasma densities (10(11)/cm(3) electron densities) and stable plasma potentials. As a result, ion energy distributions typically consisted of a single peak well separated from zero energy, Mean ion energy vari ed inversely with pressure, decreasing from 13 to 9 eV as the discharg e pressure increased from 20 to 60 mTorr. Half-widths of the ion angul ar distributions In these experiments varied from 6 degrees to 7.5 deg rees, corresponding to transverse energies from 0.13 to 0.21 eV. Durin g the course of the experiment, ion energies gradually decreased, prob ably due to the buildup of contaminants on the chamber walls. Cell wal l temperature also was an important variable, with ion fluxes to the l ower electrode increasing and the ion angular distribution narrowing a s the cell temperature increased. (C) 1997 American Institute of Physi cs.