A SILICIDATION-INDUCED PROCESS CONSIDERATION FOR FORMING SCALE-DOWN SILICIDED JUNCTION

A process consideration for forming silicided shallow junctions, arisi ng from silicidation process, has been discussed. The CoSi2 shallow pn junctions formed by various schemes are characterized. The scheme th at implants BF2+ ions into thin Co films on Si substrates and subseque nt silicidation yields good junctions, but the problems about the dopa nt drive-in and knock-on of metal deeply degrade this scheme. In the r egime 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 silic idation, dominates the leakage. A high-temperature pre-activation prio r to Co deposition reduces the perimeter leakage to 0.038 nA/cm, but w hich deepens the junctions.