The performance of semiconductor devices becomes increasingly sensitive to details of the depth distribution of dopants as device dimensions are reduced. In this paper, limitations on the control of dopant distributions resulting from implantation into single-crystal silicon due to ion channeling are examined for a range of ion atomic numbers and energies characteristic of semiconductor device fabrication. Implantation profiles were obtained by 1 MHz differential capacitance–voltage profiling and by secondary ion mass spectroscopy for silicon substrates implanted at angles from accurately channeled alignment to ’’random equivalent’’ orientation. The critical angle as calculated from an existing computer fit to the Moliere continuum potential was used to scale the angular dependence of the implantation profiles. Ion channeling is seen to have important consequences not only for the deeply penetrating regions of the dopant profile but for the near-surface profile as well. The results of this study indicate that to minimize the extent of unintentional channeling, alignment of the ion beam to the nearest low-index crystallographic direction must be at angles exceeding twice the critical angle and that the angle required can exceed the commonly used seven degree tilt angle, especially for ions of large atomic number at low energy.