STRUCTURAL INVESTIGATION OF SELF-ALIGNED SILICIDATION ON SEPARATION BY IMPLANTATION OXYGEN

Self-aligned silicidation is a well-known process to reduce the source , drain, and gate parasitic resistances of submicron metal-oxide-semic onductor devices. This process is particularly useful for devices buil t on very thin Si layer (similar to 1000 Angstrom or less) on insulato rs. Since the amount of Si available for silicidation is limited by th e thickness of the Si layer, once the Si in the source and drain regio n is fully consumed during silicidation, excessive silicide formation could lead to void formation near the silicide/silicon interface benea th the oxide edge. In this article, we study the effects of different metals (Ti, Ni, Co, and Co/Ti bilayer) with varying thickness on the f ormation of voids. A change in the moving species during lateral silic ide formation was found to be the likely cause for the voids, even if the metals are the moving species during silicidation in the thin film case. (C) 1997 American Institute of Physics.