This paper describes a physically based Monte Carlo model and simulator for accurate simulation of BF2 ion implantation in (100) single-crystal silicon. An improved electronic stopping model and a damage generation model have been developed and implemented in the simulator. These new, physically based, models greatly improve the capability for predicting BF2 as-implanted profiles. The profile dependence on the implant tilt and rotation angles as well as on the implant dose and energy can be very well predicted over the energy range from 15 to 65 keV.