Transport of ions during ion implantation

An efficient scheme for the description of long-mean-free-path particle transport at a kinetic level has been extended to a case where particle distributions are highly anisotropic: implantation of ions into a solid. The method calculates the scattering rate of particles throughout a region and obtains the particle distribution from the scattering rate. The scattering rate is found by using a numerical form of a propagator to solve an integral equation. The propagator is the probability 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 propagator can be computed efficiently and accurately for an arbitrary angular distribution of scattered particles as compared to other computer models. The method is illustrated in application to implantation of dopants into silicon. copyright 1996 The American Physical Society