Calculations of plasma sputtering including the effect of the surface floating potential

The velocity distribution of plasma ions is altered significantly when the ions pass through the electrostatic, surface floating potential. The average energy of an ion can increase by more than a factor of three as a result of this potential and the effect on sputtering can be significant. In this paper, the effect of the surface floating potential on sputtering is calculated using a Monte Carlo code. This code incorporates a simulation of the velocity distribution of plasma ions incident on a surface with a floating potential. The effect of the surface floating potential is also included in a new plasma sputtering yield analytical model. Calculations of plasma sputtering with the new model are compared with Monte Carlo results. Expressed in terms of the ion plasma temperature and the surface floating potential, the new model should provide a fast and accurate means to calculate sputtering in fusion experiments. (orig.)