IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Tuesday Sessions
       Session PS-TuP

Paper PS-TuP17
Influence of High Power Densities on the Composition of Pulsed Magnetron Plasmas

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Plasma Deposition, Modeling, and Emerging Applications Poster Session
Presenter: A.P. Ehiasarian, Sheffield-Hallam University, UK
Authors: A.P. Ehiasarian, Sheffield-Hallam University, UK
K.M. Macak, Sheffield-Hallam University, UK
R. New, Sheffield-Hallam University, UK
W.-D. Münz, Sheffield-Hallam University, UK
U. Helmersson, Linköping University, Sweden
Correspondent: Click to Email
The application of high power pulses with peak voltage of -2 kV and peak power density of 3 kW.cm@super -2@ to magnetron plasma sources is a new development in sputtering technology. This study presents evidence of multiply charged Cr and Ti metal ions in the dense plasma region of the high power pulsed magnetron discharge and a substantially increased metal ion production compared to continuous magnetron sputtering. The average degree of ionisation obtained from growth rate measurements of the Cr metal flux generated in the plasma source was 30 % at a distance of 50 cm. The high power is applied to ordinary magnetron cathodes in pulses with short duration of typically some tens of microseconds in order to avoid a glow-to-arc transition. An Ar pressure of typically 0.4 Pa (3 mTorr) is maintained during the discharge. The time evolution within a pulse of the optical emission from Ar@super 0@, Cr@super 0@, Cr@super 1+@, and Cr@super 2+@ showed that at low power (0.2 kW.cm@super -2@) Cr and Ar excitation develops simultaneously. At higher powers (3 kW.cm@super -2@) a distinct transition from Ar to Cr plasma within the duration of the pulse was observed. Optical emission from the various species in the plasma showed an increase in metal ion-to-neutral ratio with increasing power. These observations indicate that a threshold plasma density exists when a transition from conventional pulsed sputtering to pulsed self-sputtering (similar to cathodic arc spots) occurs. First attempts to model the time-dependence of the OES signals are discussed.