ION ENERGY AND ANGULAR-DISTRIBUTIONS IN INDUCTIVELY-COUPLED RADIO-FREQUENCY DISCHARGES IN ARGON

We report measurements of the energies and angular distributions of po sitive ions in an inductively coupled argon plasma in a Gaseous Electr onics Conference Reference Cell. Use of two separate ion detectors all owed measurement of ion energies and fluxes as a function of position as well as ion angular distributions on the discharge centerline. The inductive drive on our system produced high plasma densities (up to 10 (12)/cm(3) electron densities) and relatively stable plasma potentials . As a result, ion energy distributions typically consisted of a singl e feature well separated from zero energy. Mean ion energy was indepen dent of rf power and Varied inversely with pressure, decreasing from 2 9 to 12 eV as pressure increased from 2.4 to 50 mTorr, The half-widths of the ion angular distributions in these experiments varied from 5 d egrees to 9 degrees, or equivalently, the transverse temperatures vari ed from 0.18 to 0.29 eV with the distributions broadening as either pr essure or rf power was increased. (C) 1996 American Institute of Physi cs.