Extremely Thin Proximity Platinum Silicide Formation Process Using Continuous-Wave Laser Scanning Anneal

Abstract

Series resistance reduction becomes a very difficult challenge for extremely scaled MOSFETs. Proximity silicidation has been widely investigated to form a thin silicide as close to the gate edge as possible, but inherent nonuniformity of the silicide thickness was the limiting factor for practical application. In this work, a novel silicidation process primarily heats the metal layer first using a continuous-wave laser scanning anneal to confine the silicidation process only to the interface of the silicon substrate and the metal layer. As a result, a 2-nm-thick layer of platinum silicide was formed. The resistivity of platinum silicide was $52.5~\mu \Omega \cdot $ cm, similar to the results obtained using the rapid thermal annealing process. It will be possible to realize true proximity silicidation using the continuous-wave laser scanning anneal process.