Improved Salicide Process With Multilayer Silicide Formation
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
The use of diffusion interaction when depositing Ti films over exposed silicon junctions within silicon integrated circuits (ICs) results in the formation of TiSi2 over the exposed gate polysilicon and bare doped Si junctions, without reaction over the field oxide (Fig. 1). The non-reacted metal is subsequently selectively removed using a hot peroxide etching solution (Fig. 2). TiSi2 is most favored because of its low resistivity and the Ti provides a more uniform and reproducible reaction with the silicon. The WSi2, though yielding a higher resistivity than TiSi2, is more stable relative to basic peroxide solution solubility, and less reactive, as deposited, to SiO2 in the field oxide or sidewall oxide spacers on the polysilicon gate line.