Fluorine effects on silicidation of BF/sub 2//sup +/-implanted narrow poly lines

Abstract

The use of BF/sub 2//sup +/ for p/sup +/ source/drain implant has resulted in void formation in TiSi/sub 2/ films on p/sup +/ poly and diffusion regions due to the interaction between fluorine outdiffusion and Ti silicidation. When using B/sup +/ instead of BF/sub 2//sup +/, no voids were observed. Deposition of a TEOS layer (150 /spl Aring/) as a fluorine gettering source before p/sup +/ activation anneal reduces the number of voids formed considerably. The sheet resistance of the silicided p/sup +/ narrow poly has improved substantially with the reduction or elimination of the fluorine-induced effects.