AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS-TuM

Paper PS-TuM10
Simplified Model for Calculating the Pressure Dependence of a DC Planar Magnetron Discharge and Experimental Verification

Tuesday, November 5, 2002, 11:20 am, Room C-103

Session: Atmospheric Pressure and Other Emerging Plasma Applications
Presenter: G. Buyle, Ghent University, Belgium
Authors: G. Buyle, Ghent University, Belgium
D. Depla, Ghent University, Belgium
K. Eufinger, Ghent University, Belgium
W. De Bosscher, Bekaert Advanced Coatings, Belgium
J. Haemers, Ghent University, Belgium
R. De Gryse, Ghent University, Belgium
Correspondent: Click to Email
A simplified model for the DC planar sputter magnetron discharge allowing to simulate the pressure dependence over a wide range is presented. The model is based on the assumption that the discharge is built up by arch shaped regions which are determined by the orbits of the electrons emitted from the cathode by ion bombardment (secondary electrons). This assumption, combined with relatively simple schemes for the ionization, target erosion and secondary electron production, forms the core of the simplified model. Although the presented model has not the same accuracy as more advanced models based on the Monte-Carlo method, it has the major advantage of being much less computing intensive. This allows for quickly assessing the influence of a variety of discharge parameters and has proven to be well sufficient to explain our experimental results. We observed that at high gas pressures (above approximately 0.5Pa) there is a very weak pressure dependence of the observed discharge parameters, but for lower pressures an increase in the discharge voltage, cathode sheath thickness and erosion profile width is observed. Our modeling revealed the necessity to integrate recapture of secondary electrons by the cathode to explain the observed pressure dependence. To our knowledge, recapture in planar magnetron discharges has not been acknowledged yet. This is because the small initial energy of the secondary electrons, which enables recapture, is neglected in recently published simulations. Given the good agreement between experiment and simulation in this study, it appears that recapture is essential for accurately modeling the planar magnetron discharge at low pressures and that the presented model, in spite of its simplifications, is a valuable tool for this.