Formation of NiSi-silicided p~+n shallow junctions using implant through silicide and low temperature furnace annealing

摘要

NiSi-silicided p~+n shallow junctions are fabricated using BF_2~+ implantation into/through thin NiSi silicide layer (ITS technology) followed by low temperature furnace annealing (from 550 to 800°C). The NiSi film agglomerates following a thermal annealing at 600°C, and may result in the formation of discontinuous islands at a higher temperature. The incorporation of fluorine atoms in the NiSi film can retard the formation of film agglomeration and thus improve the film's thermal stability. A forward ideality factor of about 1.02 and a reverse current density of about 1nA/cm~2 can be attained for the NiSi(310A)/p~+n junctions fabricated by BF_2~+ implantation at 35 keV to a dose of 5x10~(15)cm~(-2) followed by a 650°C thermal annealing; the junction formed is about 60nm measured from the NiSi/Si interface. Activation energy measurements show that the reverse bias junction currents are dominated by the diffusion current, indicating that most of the implanted damages can be recovered after annealing at a temperature as low as 650°C.