Refractory metal silicides for VLSI applications

Results of a recent program undertaken at Bell Laboratories on silicide gate technology are reviewed with particular reference to the TaSi2/n+ poly-Si structure. This high-conductivity refractory gate structure greatly alleviates the layout and routing problems due to large RC time constants of fine-line poly-Si interconnects. This review contains a discussion of the metallurgical effects, associated with sintering metal and metal–silicon alloy films on polycrystalline silicon, oxidation behavior of silicides, their MOS (process) compatibility, the generic reliability, and trade-offs involved in the selection of a silicide from the group TiSi2, TaSi2, MoSi2 and WSi2.