Suppression of lateral silicide formation in submicron TiSi2 ohmic contacts to heavily doped p-type silicon

A lateral silicidation problem has been found in the conventional self-aligned titanium disilicide (TiSi2) process for making ohmic contacts to heavily doped p-type (p+) silicon in the submicron domain. Two solutions curtailing the lateral Si migration and the resulting lateral silicide formation are presented: an additional low-temperature nitrogen anneal and an interfacial carbon layer. Excellent ohmic contacts with a minimum area of 0.06 μm2 and a spacing of 0.2 μm are demonstrated with both solutions.