Effects of laser annealing (LA) on the formation of silicided shallow junctions have been studied. The junctions are made by P+ implantation into thin Co films on Si substrate and subsequent drive-in/silicidation. Various implant and annealing conditions are examined. Conventional furnace annealing (CFA) is also undertaken. Good junctions can be achieved only by using low-temperature CFA due to the severe diffusion of knock-on Co atoms at high temperatures. The junctions formed by LA processing are poor in this scheme. However, the junctions formed by CFA only show small change of the dopant redistribution and the Co penetration after a subsequent LA. In addition, the silicide crystallinity and the junction characteristics can be further improved using a proper LA power. The results indicate that the laser-recrystallization technique is a promising technique for the fabrication of three-dimensional devices.