Published online by Cambridge University Press: 28 February 2011
The self-aligned-silicide (SALICIDE) process was developed to overcome the conductivity and contact resistance limitations associated with very shallow junctions. However this process is fundamentally limited by the roughening and the consumption of the silicon substrate that occurs during its selective reaction with metal. As junctions scale to smaller dimensions, me silicon consumption must also be scaled so mat the suicide does not consume the junction. The use of argon gas atmospheres during titanium suicide formation leads to more silicon consumption (75%) than can be explained simply on the basis of suicide formation. Lateral loss of silicon into the metal surrounding patterns is believed to be the mechanism responsible for this excess silicon consumption. More surprisingly, nitrogen annealing, which suppresses lateral suicide formation, also leads to an anomalously large (50%) silicon consumption. Suicides formed on amorphous substrates during the concurrent formation of junctions and suicides result in even more silicon consumption.