Under material treatment in glow discharge plasma, the ion flow at the target surface is generally supposed to be homogeneous. But on targets with structural or compositional inhomogeneity a surface relief is formed in the course of time. This can result in ion flow focusing at the relief tops due to electrical field line concentration and their more intensive sputtering. On the other hand, the back flow of sputtered material from plasma on the target surface can be higher at the relief tops as well. The combined effect of the both processes on relief evolution was not investigated before.
In this work, an influence of ion and sputtered atom flow inhomogeneities on the target surface relief evolution in glow discharge is studied. A mathematical model is developed, which includes equations for ion and sputtered atom flows and electric field distribution in the vicinity of the target surface with a periodical surface relief. In case the relief amplitude is rather small, their approximate analytical solution is obtained by the perturbation method. An equation describing the relief amplitude time evolution is derived. Conditions are found under which one of the processes of sputtering and deposition is dominant and relief growing or smoothing takes place.
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