The achievement of ultra-shallow doping profiles by ion implantation requires low energy implants and minimum thermal budgets. In this case, the profile is generally more sensitive to the implant parameters, including implant angles and dose. A detailed study has been performed of the dependence of boron and arsenic profiles on tilt angle, rotation angle, and dose for energies down to 15 keV for BF2+ and As+ implants in (100) Si wafers. The major axial and planar channels have been determined using critical angle analysis and are in agreement with experimental observations. In addition, computationally efficient models have been developed for BF2 and As implants which accurately account for the boron and arsenic profile dependence on tilt angle, rotation angle, and dose in addition to energy.