A differential Hall effect technique has been developed to obtain doping profiles at a depth resolution down to 2 nm with junction depths of about 20 nm. We have determined the electrical characteristics of 5x10(14) Sb+ cm(-2) implanted in (100) silicon at an energy of 5 keV. A comparison was made between carrier concentration profiles and secondary ion mass spectroscopy measurements of the atomic profiles as a function of annealing temperature. We have profiled single energy implants of antimony and also double implants; the latter enables complete profiles to be measured down to the background level of about 10(18) cm(-3). (C) 2004 American Institute of Physics.