Nickel silicide formation using multiple-pulsed laser annealing

Abstract

The effect of multiple-pulsed laser irradiation on Ni silicide formation in Ni(Ti)∕Si system was studied. A layered structure consisting of both crystalline NiSi2 and Ni-rich Ni–Si amorphous phases with a protective TiOx overlayer was formed after five-pulsed laser annealing at 0.4Jcm−2. Different solidification velocities caused by a variation in the atomic concentration across the melt have led to the formation of this layered structure. On the other hand, by increasing the number of laser pulses, a continuous layer of polycrystalline NiSi was obtained after a 20-pulsed laser annealing at 0.3Jcm−2 laser fluence. Its formation is attributed to a better elemental mixing which occurred during subsequent pulses. Enhancement of surface absorption and remelting of the phases formed is proposed as the mechanism governing the continuous NiSi layer formation.