US Patent 7345355 Complementary junction-narrowing implants for ultra-shallow junctions

Methods are disclosed for forming ultra shallow junctions in semiconductor substrates using multiple ion implantation steps. The ion implantation steps include implantation of at least one electronically-active dopant as well as the implantation of at least two species effective at limiting junction broadening by channeling during dopant implantation and/or by thermal diffusion. Following dopant implantation, the electronically-active dopant is activated by thermal processing.