Multi-ion species model with initial presheath profile for plasma source ion implantation

A numerical model simulating the time evolution of a sheath has been developed for a collisionless, cold, multi-ion species plasma. The initial presheath profile is calculated from the steady state fluid equations with a uniform source ina one-dimensional planar, cylindrical, or spherical geometry. A high negative voltage pulse is applied to the target and the time-dependent, self-consistent potential profile is calculated from Poisson's equation coupled with collisionless fluid equations for the multi-ion species and a Boltzmann approximation for the electrons. In addition to the density and potential profile, the simulation yields the ion current to the surface and the energy spectrum of the each of the ion species hitting the surface. (C) 1999 Elsevier Science S.A. All rights reserved.