In this paper, an improved modeling approach is described for simulating as-implanted boron impurity profiles for B+ and BF2 + implants into single-crystal silicon. This method uses the sum of two Pearson distribution functions to account for the nonchanneling and channeling components of the implant distribution. The ratio of the two Pearson functions varies with dose, which accounts for the change in the degree of channeling with dose. This modeling approach has been compared with experimentally measured SIMS profiles for a wide range of energies and doses for shallow B+ and BF2 + implants. The excellent agreement indicates that this method offers a large improvement in simulation capability for B+ and BF2 + implants. In addition, this method should be applicable to accurately model other impurities which have channeling tendencies.