Co-SILICIDE, Co(Ni)-SILICIDE AND Ni-SILICIDE TO SOURCE/DRAIN CONTACT RESISTANCE

摘要

The contact resistance of Co-silicide, CoNi-silicide and Ni-silicide to sub 100 nm As and B is investigated using set of dedicated test structures with silicided segments of varying lengths, based on the Scott model of Transmission Line Structure. The impacts of salicide process variables such as the silicide thickness, capping layers and silicidation thermal budgets on the contact resistance are studied for each silicide. Co-silicidation or CoNi-silicidation on As junctions at low thermal budget results in contact resistance values similar to Ni-silicidation. For Co-silicide on B junctions the contact resistance increases strongly with increasing the silicidation temperatures. For the same thermal budget CoNi-silicidation results in significant lower contact resistance to B junctions than Co-silicidation. Similar contact resistance is obtained for CoNi-silicide and Ni-silicide on B junctions. Ni-silicide benefits from low barrier on B junctions that reduces the contact resistivity. In addition, Ni-silicide is formed at low temperatures and consumes less silicon and by this avoids the reduction of active dopants concentration at Silicide/Silicon interface.