A silicidation-induced process consideration for forming scale-down silicided junction

A process consideration for forming silicided shallow junctions, arising from silicidation process, has been discussed. The CoSi/sub 2/ shallow p/sup +/n junctions formed by various schemes are characterized. The scheme that implants BF/sub 2//sup +/ ions into thin Co films on Si substrates and subsequent silicidation yields good junctions, but the problems about the dopant drive-in and knock-on of metal deeply degrade this scheme. In the regime that implants the dopant into Si and then Co deposition, however, a large perimeter leakage of 0.1 nA/cm is caused. Generation current, associated with a defect-enhanced diffusion of Co in Si during silicidation, dominates the leakage. A high-temperature pre-activation prior to Co deposition reduces the perimeter leakage to 0.038 nA/cm, but which deepens the junctions.<
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