A kinetic study of the C49 to C54 TiSi2 conversion using electrical resistivity measurements on single narrow lines

We describe a simple quasi-in situ resistivity technique and its application to the study of C49 to C54 TiSi2 conversion in narrow (0.1-1.0 μm) lines. This technique allowed comparison of both aggregate conversion versus time at temperature behavior and individual-line conversion versus time behavior for silicide lines of different linewidths. As linewidth decreased, the aggregate conversion versus time at temperature behavior slowed, and the conversion behaviors of individual lines having the same linewidth became more variable. Both of these observations are consistent with a nucleation-site-density controlled reaction under conditions of low nucleation site density. Correlations were also found between individual line behaviors and resistance to agglomeration; resistance to agglomeration (for 0.35–1.0 μm lines already in the C54 phase) was highest for lines which had ‘‘prompt’’ conversion behaviors (as measured by the sheet resistance drop during the first minute of the conversion anneal). Additional data concerning the sensitivity of the initial sheet resistances to formation anneal conditions and linewidth is also briefly discussed.