TiSi2 Formation on Submicron Polysilicon Lines: Role of Line Width and Dopant Concentration

We report on a study of the effects of dopant concentration and linewidth on the formation of TiSi2 on polysilicon. The transformation from the C49 phase to the C54 phase is inhibited by a high concentration of either phosphorus or arsenic in blanket polysilicon films. For sub-half-micron lines, patterned in polysilicon doped with As or P, agglomeration is the key factor in the inability to produce low resistance silicide. The result is a critically shrinking process window for the attainment of low resistance VLSI interconnects.