Ion energy distribution in ionized dc sputtering measured by an energy-resolved mass spectrometer

Ion energy distribution of sputtered Ti particles in ionized de sputtering has been measured by an energy-resolved mass spectrometer. The energies of the Ti+ and Ar+ ions were measured by a Balzers PPM421 plasma monitor. The experimental results showed that the energy of sputtered Ti particles was e nhanced from 2 or 3 to about 30 eV as a coil rf power increased from 0 to 2 00 W, for a constant magnetron cathode current of 0.3A. On the other hand, when a cathode current increased from 0.1A to 0.5A for a constant coil rf p ower of 200 W, the mean energy of Ti+ decreased, as a result of the plasma quenching caused by the increase in the number of the sputtered Ti particle s. In addition, it was found that the number of Ti+ ions was saturated for cathode de currents higher than 0.3 A. The results obtained in this study d emonstrate that the ratio of the coil rf power to the magnetron cathode pow er or current is crucial to obtain a proper ionization ratio and energy of sputtered particles. (C) 1999 Elsevier Science Ltd. All rights reserved.