The effect of Co incorporation on electrical characteristics of n/sup +//p shallow junction formed by dopant implantation into CoSi/sub 2/ and anneal

The impact of Co incorporation on the electrical characteristics has been investigated in n/sup +//p junction formed by dopant implantation into CoSi/sub 2/ and drive-in anneal. The junctions were formed by As/sup +/ (30 or 40 keV, 1/spl times/10/sup 16/ cm/sup -2/) implantation into 35 nm-thick CoSi/sub 2/ followed by drive-in annealing at 900/spl deg/C for 30 s in an N/sub 2/ ambient. Deeper junction implanted by As/sup +/ at 40 keV was not influenced by the Co incorporation. However, for shallower junction implanted by As/sup +/ at 30 keV, incorporation of Co atoms increased its leakage current, which were supposed to be dissociated from the CoSi/sub 2/ layer by silicide agglomeration during annealing. The mechanism of such a high leakage current was found to be Poole-Frenkel barrier lowering induced by high density of Co traps.