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 enhanced from 2 or 3 to about 30 eV as a coil rf power increased from 0 to 200 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 power 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 particles. 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 demonstrate that the ratio of the coil rf power to the magnetron cathode power or current is crucial to obtain a proper ionization ratio and energy of sputtered particles. (C) 1999 Elsevier Science Ltd. All rights reserved.