TRANSPORT OF IONS DURING ION-IMPLANTATION

An efficient scheme for the description of long-mean-free path particl e transport at a kinetic level has been extended to a case where parti cle distributions are highly anisotropic: implantation of ions into a solid. The method calculates the scattering rate of particles througho ut a region and obtains the particle distribution from the scattering rate. The scattering rate is found by using a numerical form of a prop agator to solve an integral equation. The propagator is the probabilit y that a particle that scattered in a cell has its next scatter in any other cell of the mesh. The main focus of this work is the way this p ropagator can be computed efficiently and accurately for an arbitrary angular distribution of scattered particles as compared to other compu ter models. The method is illustrated in application to implantation o f dopants into silicon.