A novel selective Ni/sub 3/Si contact plug technique for deep-submicron ULSIs

Abstract

A contact filling-technique that utilizes polysilicon plug formation followed by Ni silicidation with a TiN barrier at the polysilicon plug bottom is described. Self-aligned complete silicidation of both shallow and deep contacts can be achieved at the same time by using the TiN silicidation stop. By using this technique in place of a polysilicon plug, low contact resistance was achieved for both n/sup +/ and p/sup +/ contacts. A completely silicided plug for both shallow and deep contact holes can be achieved at the same time. The low leakage current of junction diodes and lack of transistor characteristic degradation when using the Ni silicide plug demonstrate the integrity of the technique. >