Determination of cathode fall thickness in magnetized dc plasma for argon gas discharge

Abstract

The thickness of the cathode fall region (dc) in magnetized dc argon plasma has been investigated using two different methods, namely the axial potential distribution and the current density distribution along the glow discharge regions. The measurements have been carried out at the edge and center of the cathode surface. Dc (cold cathode) magnetron sputtering unit has been used. The radial and axial distributions of the magnetic field B, the I a-Va characteristic curves of the glow discharge and the axial potential distribution and the current density distribution have been investigated. The thickness of the cathode fall region was between 2 and 3.3 mm for the two methods in pressure (P) range of 0.53-4 mbar. It is concluded that a noticeable reduction of the cathode fall thickness (about 33%) has been found in the presence of a magnetic field and at the center of the cathode and stronger electric field at the edge of the cathode fall, and hence high rates of sputtering are expected. © 2013 The Royal Swedish Academy of Sciences.