2 ION FLUID MODEL FOR PLASMA SOURCE ION-IMPLANTATION

For plasma source ion implantation in a nitrogen discharge, there is a mixture of atomic and molecular species N+ and N2+, respectively. A t ime dependent fluid model has been developed, which models a plasma co nsisting of two species of cold collisionless ion fluids, assuming tha t the electrons are in thermal equilibrium. Following the application of a large, negative voltage pulse to the metal target, the density an d velocity of the two ion species, and the sheath evolution for a rang e of possible ion mixtures are calculated.