A two-dimensional simulation of dc magnetron discharge is performed by a hybrid of fluid and particle models. In this hybrid model, ions and bulk electrons are treated by the fluid model and fast electrons are treated by the particle model. The numerical results indicate that the number density of the fast electrons has little effect on the electric field distribution in dc magnetron discharge at 30 mTorr since the ratio of fast electrons to bulk electrons is quite low. The transport of fast electrons is, however, quite important for dc discharge because the spatial distribution of the net ionization rate is subject to the spatial behavior of the fast electrons.

Erosion of accel grids of ion engine due to sputteringa) Rev. Sci. Instrum. 81, 02B109 (2010); 10.1063/1.3271248Numerical study of the sputtering in a dc magnetron

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We simulate the erosion profiles of a rectangular planar target in the DC magnetron sputtering system. The simulation model assumes time-independent magnetic and electric fields that are not disturbed by the magnetron plasma. The electron trajectories are obtained by integrating partial orbits. The Monte Carlo technique, taking account of the differential cross section, is used to discriminate the ionization collision from the excitation and elastic collisions. Thus we determine the coordinates where an argon ion and an electron appear to indicate the erosion profiles. The calculated 3D erosion profiles are in very good agreement with those of the target actually used. This simulation technique for the sputtering process will be valuable in designing the magnet arrangement of a magnetron sputter target.

The influence of the differing magnetic field arrangements in both an unbalanced magnetron (UBM) and balanced magnetron (BM), both of which employ a dielectric substrate, on plasma characteristics has been numerically investigated under identical pressures and voltages. The UBM exhibits some interesting intrinsic characteristics with regard to the bulk plasma and the incident flux on the dielectric substrate. A property unique to the UBM is the appearance of negative plasma potential owing to the slightly excess amount of electrons when a magnetic field is arranged parallel to the axis of the bulk plasma in a cylindrical reactor and an electric field is arranged transversely to this axis. The dielectric substrate is negatively deep-biased, as compared with that in the BM, and is exposed to positive ion impact with a higher energy and flux, which will be controlled by changing the magnitude and direction of the external magnetic field.