Effects of an interposed Mo layer on the interfacial reactions of Ti/Si0.76Ge0.24 by rapid thermal annealing and pulsed laser annealing

Abstract

The thickness effect of an interposed Mo layer between Ti and Si0.76Ge0.24 films on the lowering of the formation temperature of C54 (Ti, Mo)(Si1-xGex)(2), thereby reducing Ge segregation and agglomeration of the C54 (Ti, Mo)(Si1-xGex)(2) films, is studied. Upon rapid thermal annealing, the interposed Mo layer can significantly reduce the formation temperature of C54 (Ti, Mo)(Si1-xGex)(2); however, the amount of reduction decreases with the Mo thickness. The electron/atom ratio seems to be one of the important factors in the lowering of the formation temperature of C54 (Ti, Mo)(Si1-xGex)(2). For the samples having an interposed Mo layer 0.5 nm thick a smooth C54 (Ti, Mo)(Si1-xGex)(2) film without Ge segregation can be grown after annealing at a temperature of 625-650 degreesC. For pulsed KrF laser annealing the rapid melt/solidification process allows only growth of C40 Ti(Si1-xGex)(2) or C40 (Ti, Mo)(Si1-xGex)(2) even though an interposed Mo layer is introduced into the Ti/Si0.76Ge0.24 samples, indicating that upon pulsed laser annealing the kinetic effect can dominate over the thermodynamic effect.