The diffusion and segregation of Sb and As is investigated after low-energy implantation and annealing, both rapid thermal processing and furnace annealing. We demonstrate that the absence of transient enhanced diffusion effects for Sb facilitates the fabrication of significantly shallower junctions with less dopant segregation to the surface. It is shown that Sb implantation can be used to fabricate low-resistivity ultrashallow junctions suitable for source/drain extensions in n-type metal-oxide-semiconductor field effect transistors. (C) 2004 American Vacuum Society.